Noctua is making its debut in the thermal pad market through a new partnership with experienced manufacturer Carbice. Noctua has announced it will be the exclusive distributor of Carbice pads for the retail market, starting with the NT-CP1 AM5/4 Carbice carbon nanotube thermal pad. Noctua will be presenting the NT-CP1 at Computex starting tomorrow and will launch the product in September.

As the name suggests, the new Noctua-branded thermal pad is optimized specifically for AM5 and AM4 AMD Ryzen CPUs, featuring a surface area that perfectly matches the IHS of CPUs that fit in both sockets.

The pad is made from carbon nanotubes that are designed to improve thermal conductivity over “hundreds and thousands of thermal cycles”. The carbon nanotubes achieve this by slowly conforming to the microscopic crevices of a CPU’s IHS. The pad is reinforced with an aluminum backbone that is sandwiched between the carbon nanotubes and protected on the surface with a nanoscale polymer coating.

Similar to outgoing thermal pads, the NT-CP1 is a maintenance-free solution that will last the lifetime of the CPU it is cooling. This is optimal for PC builders who want a permanent solution, unlike thermal paste, which typically needs to be replaced every three to five years. Thermal paste loses performance as it ages because repeated thermal cycles causes the paste to dry up.

The NT-CP1 represents the first thermal pad that Carbice is bringing to the DIY market. The company actively makes thermal pads for satellites, aerospace, and pre-built PCs (through a partnership with CyberPowerPC). It also recently announced a partnership with AMD, and is supplying its Ice Thermal Pad with the re-released Ryzen 7 5800X3D. Dr. Baratunde Cola, CEO of Carbice, notes that the company chose Noctua specifically to partner with due to the company’s widespread trust in the DIY community. Noctua will also assist Carbice in developing future thermal pads, suggesting that we could see an Intel version of the NT-CP1 in the future.

It may be a grim time for building a new PC due to the ever-growing expense of RAM kits, SSDs, and graphics cards, but that makes it super important to look after what you've already got and keep your PC maintained and in tip-top condition. Apart from the normal tasks of cleaning out your case's dust filters, don't forget to replace the aging thermal paste on your CPU or GPU if everything starts to run a little hotter. Dropping to its lowest-ever price on Amazon, Arctic's MX-6 thermal paste (4g) is now only $5.99, down $6 from its previous $11.99 price tag. Checking the Amazon price checker CamelCamelCamel, we can see that this new $5.99 price point is an all-time low for this product.

• Grab this deal at Amazon

Arctic's MX-6 thermal paste is a very popular choice for enthusiasts looking to add a premium cooling solution to their very important CPUs and GPUs. Thermal paste provides a way of getting a good thermal contact between the integrated heat spreader (IHS) of the processor and the cold plate of your cooler. A lot of coolers come with a default paste already applied, but this isn't always the best option, and temperatures of CPU operations can be improved with more heat-conductive thermal paste options.

There is a new Arctic MX-7 thermal paste available, and it boasts better performance, but it's also a fair bit more expensive than this deal. Also, this particular product is available directly from Arctic via Amazon, and not a third-party reseller, so you avoid possible forgeries.

We haven't reviewed Arctic's MX-6 thermal paste, but we have tested the previous MX-4 and MX-5 products, and they both appeared high up in the benchmarking charts. Arctic's MX-6 thermal paste is our recommended pick for runner-up in the best premium thermal pastes, with Thermal Grizzly Duronaut being the top pick. The price of the Thermal Grizzly Duronaut (6g) is $19.99, which gives you an idea of how good the price on this Arctic MX-6 really is.

If you're looking for more savings, check out our Best PC Hardware deals for a range of products, or dive deeper into our specialized SSD and Storage Deals, Hard Drive Deals, Gaming Monitor Deals, Graphics Card Deals, Gaming Chair, Best Wi-Fi Routers, Best Motherboard, or CPU Deals pages.

Arctic has a well-earned reputation for its thermal pastes, with its MX-6 being one of the best thermal pastes on the market. The company has introduced the MX-7 to stay ahead of the competition. It claims the MX-7 is the company's coolest thermal paste to date, with prices ranging from $6-10.

Having launched three years ago, the MX-6 still feels quite new, but in a competitive market where new products come out every year, staying relevant is key. The MX-7 features a new formula that Arctic understandably keeps under wraps. Still, the company shares that the MX-7 boasts low adhesion for even distribution, high viscosity for flow resistance, and high cohesion for more durable bonding.

• Arctic MX-7 2 grams: $6.89
• Arctic MX-7 4 grams: $7.39
• Arctic MX-7 4 grams with six MX-Cleaner wipes: $9.59
• Arctic MX-7 8 grams: $8.59

Arctic takes a different approach from other thermal paste brands by not emphasizing thermal conductivity values for its products. As detailed in the specification sheet, the MX-7 is up to 22% less viscous than the MX-6 and approximately 12% denser than its predecessor. In Arctic's own testing, using a Core Ultra 9 285K at 4.5 GHz and drawing around 284W in an ambient temperature of 25 degrees Celsius, the MX-7 managed to deliver temperatures about 3% cooler than the MX-6 and up to 6% cooler than the MX-4.

Arctic MX-7 Specifications

Rest assured, the thermal paste is completely safe to use with direct-die cooling solutions because it's not electrically conductive or capacitive. This means you don't need to worry about any risk of short circuits or discharges that could damage your devices.

While the MX-7 is less thick than the MX-6, it still has a nice, viscous consistency. Arctic suggests avoiding spreading the paste with a spatula. Instead, applying it in a simple cross pattern is best, and let your CPU cooler do the magic. The pressure from the cooler will evenly spread the MX-7, filling in any gaps and giving you complete coverage. This helpful tip also works well for coolers with direct-touch heat pipes.

Since the MX-7 is non-capacitive and non-conductive, it's simple to wipe away excess or old applications with ease. Arctic also offers a separate MX Cleaner wipe that's perfect for cleaning thermal paste. Plus, these wipes can be purchased together as an MX-7 bundle for added convenience.

You can easily find the MX-7 for sale on Amazon. The latest thermal paste isn't much pricier than the previous version. To give you an idea, the 2-gram and 8-gram syringes cost just about $1.40 more, while the other MX-7 options are less than $0.50 more expensive than their older versions.

With so many Arctic knockoffs out there, it's a good idea to buy your MX-7 from trusted retailers. Arctic has also improved its MX Authenticity Check system, allowing you to easily verify your product’s authenticity using a unique QR code for each item. This helps ensure you get the real deal and have peace of mind with your purchase.

Amech, the maker of the thermal paste that stinks and damages coolers, has known about the issues with its product since at least October 2024, according to Igor Wallosek from Igor's Lab. Instead of addressing the problem that damages coolers and can potentially lead to damage to expensive CPUs or GPUs, the company kept producing and selling the thermal grease. SGT-4 appears to be a chemically reactive blend that stinks due to acidic vapors, permanently damages CPUs and coolers with pitting from corrosion, and causes coolers to glue to the chip.

The situation deteriorated recently when Amech accused Wallosek of destroying its reputation and launched a counter-marketing campaign across Korean social networks and Igor's YouTube channel, prompting the journalist to fight back.

According to Igor Wallossek's email exchange with the company, Amech was explicitly warned about the chemical instability and possible corrosive effects of its SGT-4 paste as early as October 2024. Our colleague informed the manufacturer of abnormal results from SGT-4 tests: a sharp, vinegar-like smell upon heating, bondline thickness doubling between 20°C and 80°C, and visible hardening after fewer than 10 cycles.

Amech replied with thermogravimetric data claiming 'almost zero weight loss' up to 120°C, arguing that the paste remained stable, but offered no credible explanation for the odor or the rapid structural change that Igor had observed. The company also did not reveal how the paste was made or which additives it used. When asked to provide full safety data sheets (SDS), Amech sent REACH and RoHS certificates, which turned out to be generic forms without testing annexes, dates, or formulation data, so they were insufficient for European compliance. Wallossek advised changing the silicone oil, but it does not look like Amech followed the advice.

On October 16, 2024, Igor's Lab published an article about the SGT-4 thermal paste. Instead of the usual benchmark graphics, the article listed raw laboratory data and cautioned that the material used in SGT-4 might corrode copper over time. A few weeks later, Amech responded that the smell came from a PDMS additive supplied by BYK from Germany and that the additive contained amino groups, which BYK considered safe. Meanwhile, BYK's 'safe' label referred only to CLP and GHS toxicology categories, not to compatibility with metal oxide surfaces. Thus, the product was legally compliant yet chemically destructive. Under heat and moisture, amino-functional siloxanes promote adhesion, hydrolysis, and complex formation with copper and nickel oxides. Visually, greenish or bluish deposits typical of copper salts can be observed.

Both RoHS and REACH certificates eventually sent by Amech were worthless as they provided no evidence about the actual content of SGT-4 or its corrosive behavior. RoHS confirms the absence of restricted heavy metals or brominated flame retardants, not the chemical stability of a compound. REACH asserts that substances are registered or imported under 1 ton per year, but gives no insight into additives, concentrations, or structures.

But the problem could be much bigger than just one harmful thermal paste on the market. Amech claims to be a two-person workshop in Pohang that manually produces small batches and lacks resources for proper documentation or a functioning website. However, if this were the case and Amech truly manufactured the paste itself, removing or replacing the amino additive would have been simple. To that end, Wallosek suspects that Amech just repackages premade substance from another supplier, which means that there could be other potentially dangerous thermal greases on the market.

Some thermal pastes are good for air cooling, others for liquid cooling, some are generally efficient, others are not. But as our colleague Igor Wallosek discovered, there is a thermal paste that stinks and damages coolers. That thermal paste — Amech (Aimac) SGT-4 made in South Korea — appears to be quite popular in online stores around the world because it is cheap and gets favorable user reviews. Yet, SGT-4 appears to be a chemically reactive blend that stinks due to acidic vapors, permanently damages CPUs and coolers with pitting from corrosion, and causes coolers to glue to the chip. The TIM also doesn't meet its thermal ratings due to the pitting.

SGT-4 (not among the best thermal greases that Tom's Hardware has tested) is based on PMDS; however, chemical testing and user evidence indicate that it is not a standard silicone-based thermal paste, as it adds a reactive acetoxy-curing RTV silicone, a substance that seems to release acetic acid when it contacts moisture, based on Igor's findings. This additive — likely methyltriacetoxysilane, according to Igor's Lab — was apparently used to make the grease cohesive and adhesive when applied at thin bond lines, but its reaction produces acidic vapors that cause metal oxidation and the smell of vinegar. 

During operation, the acetic acid gradually corrodes copper surfaces, causes pitting and discoloration, and glues surfaces together, according to both Igor and his readers. Although the substance glues the cooler to the CPU, Igor Lab's measurements found that thermal conductivity was far below the manufacturer's claims, probably due to pitting (called 'ant nest corrosion') caused by the acid. Normally, thermal greases are applied to fill in the imperfections of the surfaces of the cooler and the cooled system, thus enhancing cooling performance. This appears not to be the case with the SGT-4, as instead of filling the voids, it creates new ones.

Community posts on Quasarzone — a South Korean website — confirm a host of problems, such as erased CPU markings, copper discoloration, and pitting on copper. Despite the fact that Amech prefers to be an incognito 'brand' with no website, users from South Korea have found a way to contact it. 

The manufacturer's reaction was not exactly supportive: instead of addressing the evidence, Amech representatives issued personal insults, dismissed the findings as baseless, and insisted the product complied with RoHS and REACH environmental standards that prove that the grease does not contain any hazardous substances. Meanwhile, such certifications are irrelevant to metal reactivity or being precursors of hazardous substances, especially under normal usage conditions.

To make matters even worse, the Amech reps repeatedly referred to Igor's unveilings as 'a person from Germany' to discredit the source while avoiding any technical rebuttal. They have never disclosed the paste's composition either. As a result, by mid-October, trust in the company had collapsed completely among the community.

Chinese manufacturer Coracer has introduced the GPE-01 graphene thermal pads for AMD's AM5 processors, which are currently some of the best CPUs you can buy. Previously, the GPE-01 was compatible only with Intel's LGA1851 and LGA1700 chips.

Traditional thermal paste has existed for decades. While it may not be the most exciting component, it effectively fulfills its purpose. In recent years, however, enthusiasts have developed a preference for alternative materials to fill the gap between the processor and CPU cooler. As a result, options like liquid metal and thermal pads have become more common in the market and on our page of the best thermal paste and TIM we've tested.

Segotep introduced the GPE-01 (21 x 44mm) at the end of last year, tailored for the elongated designs of Intel's LGA1851 and LGA1700 processors. While Segotep is a well-established brand in the Chinese market, we were unaware of Coracer. A Google search brought no results, leaving us uncertain whether Coracer is a new sub-brand of Segotep or if the original manufacturer licensed the GPE-01 to another brand.

Regardless, the AM5 variant of the GPE-01 measures 32 x 32mm and aligns perfectly with the processor's integrated heat spreader (IHS). While AM5 chips feature an unconventional design, the GPE-01 adopts a square shape that covers the entire IHS but doesn't overreach to the corners.

According to Coracer, the GPE-01 utilizes a combination of graphene and silicon to achieve an eye-popping thermal conductivity up to 130 W/m·K. The thermal pad is encased in an isolating material that stops the graphene from creating a short circuit with the processor. Graphene is known for its excellent conductivity. As a result, manufacturers increasingly utilize this material in thermal pads and paste.

GPE-01 Graphene Thermal Pad Specifications

German-Swiss cooling specialist Arctic Cooling has emailed Tom's Hardware with updated details on its MX Authenticity Check system. The QR code-based system assures customers that they can enjoy "safety with genuine Arctic quality." The company confirmed that the program is in response to counterfeit pastes.

Arctic reiterates the common wisdom that "thermal paste plays a central role in any PC build that relies on effective cooling, as it ensures optimal heat transfer from the processor to the heat sink." We have extensive articles testing individual new pastes, compounds, pads, and our bumper round up with over 50 pastes tested and ranked (updated earlier this year). Arctic MX pastes rub shoulders with the best, and might be the nearest we have to an industry standard, as all Tom's Hardware CPU testing is performed with a blob of MX-4 betwixt IHS and cooler block.

Our email from Arctic mentions that counterfeits are becoming "increasingly prevalent," which seems to be why the new product verification system has been introduced.

So, how does it work? Well, Arctic has a live MX Authenticity Check site already, so you can go and see for yourself. In brief, when you receive your new thermal paste from Arctic or one of the many retailers that carry these compounds, you first check the seal, scratch it to reveal a QR code, scan it with your mobile, and then verify it online. According to Arctic, the whole process takes "just a few seconds." After you are done, you will know if your paste is genuine Arctic gloop, or a dastardly doppelgänger dupe. While the program has been around for a while, the new 4-step graphic (seen above) is a new feature to make the verification process more readily apparent to customers.

Is the Arctic paste tube in your spares drawer genuine?

Many PC enthusiasts will already have a tube or two of thermal paste in their toolboxes, tool bags, or drawers. We even reported on tests showing 20-year-old paste – an ancient syringe of Arctic Cooling Silicone Paste – is still useful, despite being left in the rearview mirror by the latest formulations. But without the new QR-code system in place, there doesn't seem to be a way to confirm that your Arctic paste is genuine unless you bought it directly from the company.

A user review of the Ryzen 5 7400F at Bilibili suggests performance similar to the 7500F with superior binning, at least when the processor is not thermally constrained (via Harukaze at X). Further inspection by delidding the CPU reveals that AMD has opted for simple thermal paste instead of Solder Thermal Interface Material (STIM) between the Integrated Heat Spreader (IHS) and the CPU die, likely as a cost-saving measure. With a low price tag of just $115 (in China), AMD had to cut corners somewhere and it seems we've found the answer.

To recap, last month AMD silently released the hexacore Ryzen 5 7400F, standing as the most affordable Raphael-based CPU for consumers. What separates the 7400F from the 7500F is inferior binning as reflected in the clock-speeds. The Ryzen 5 7400F offers six cores and twelve threads based on AMD's Zen 4 architecture. Employing Raphael silicon underneath nets it 32MB of L3 cache and 6MB of L2 cache, with a base TDP of 65W (88W PPT). In terms of clock speeds, the 7400F is advertised with a base frequency of 3.7 GHz, reaching as high as 4.7 GHz, 300 MHz slower than the 7500F.

The reviewer's test bench features the Ryzen 5 7400F paired with DDR5-6000 CL36 memory on MSI's MPG 850 Edge Ti WiFi motherboard. The Bilibili-based reviewer specified two AIOs for the test namely: the Taiyu T360 Pro and the DeepCool LP360. With all settings at default and only EXPO enabled, the Ryzen 5 7400F falls 6% short of the 7500F in the Cinebench R23 single-core benchmark.

At the default 88W PPT, the 7400F easily hits Tjmax (95 degrees Celsius) with a liquid cooler, a direct consequence of the inferior interface material. When the package power is lifted to around 100W, the CPU hits 105 degrees Celsius and promptly shuts down. After manually adjusting the voltage and frequency in the BIOS, the 7400F clocked at 5.05 GHz with a temperature of 96 degrees Celsius.

The reviewer didn't test the 7400F with PBO, but you'd probably have to spend more time fine-tuning the offsets to hit 5 GHz at comfortable temperatures. STIM has several advantages for CPUs as it's not only more thermally conductive but also lasts longer than normal thermal grease. Again, this has no perceivable impact on the average consumer who doesn't have the time or isn't interested in overclocking. For enthusiasts or even budget gamers looking to get the most out of their processor, the Ryzen 5 7500F should still be the superior choice.

A new colloidal thermal interface material (TIM) promises to significantly outperform commercially available liquid metals like Thermalright, Thermal Grizzly, and Coollaboratory products. Researchers at the Cockrell School of Engineering, part of the University of Texas, summarize their new invention as a mechanochemistry-engineered mix of Galinstan alloy and ceramic aluminum nitride. The bottom line is that the new TIM can outperform the best commercial liquid metal alternatives by between 56% and 72%, highlights Golem.de.

According to the researchers, the new TIM could reduce the cost and complexity of cooling power-hungry systems. “The power consumption of cooling infrastructure for energy-intensive data centers and other large electronic systems is skyrocketing,” noted Guihua Yu, professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering and Texas Materials Institute. “That trend isn’t dissipating anytime soon, so it’s critical to develop new ways, like the material we’ve created, for efficient and sustainable cooling of devices operating at kilowatt levels and even higher power.” The scientists go on to underline the fact that around 40% of a data center's energy expenditure is on cooling.

A key cooling performance figure shared by the researchers is that the new TIM can cut the energy needed for the cooling pump by 65%. Its performance is such that it “can enable sustainable cooling in energy-intensive applications, from data centers to aerospace, paving the way for more efficient and eco-friendly technologies,” said Kai Wu, lead author in Yu’s lab. It is expected to be a compelling solution in AI data centers.

The major difference with this new TIM is how it is made into a colloidal substance using mechanochemistry. Basically, a liquid metal alloy called Galinstan (gallium, indium, and tin), is mixed with microscopically dispersed insoluble particles of ceramic aluminum nitride. A mechanochemistry technique ensures the optimal dispersion of the ceramic in the liquid metal – resulting in its attractive thermal properties.

Golem.de, which seems to have accessed the full scientific paper, notes that the researchers “achieved heat transfer resistances that were between 56 and 72 percent lower than the best liquid metals.”

Unsurprisingly, the Texas-based boffins frame the new thermal material as a great solution for energy-hungry data centers. However, their awareness of the commercially available liquid metal TIM products that are popular among PC enthusiasts is encouraging – it should speed the new colloidal TIM into the hands of Tom’s Hardware readers. In other words, we hope the researchers’ mention of brands like Thermal Grizzly will mean this new TIM’s manufacturing method and ingredients can be commercially licensed sooner rather than later.

Choosing the best thermal paste may sound simple, but a dizzying array of options can turn this seemingly easy choice into a time-consuming and confusing task. We tested 37 different thermal compounds with AMD’s Ryzen 9 9950X and over 90 thermal compounds with Intel Core i9 CPUs to help you find the best one to help cool your CPU.

What is thermal paste? Thermal paste is a compound designed to minimize microscopic air gaps and irregularities between the surface of the cooler and the CPU's IHS (integrated heat spreader), the piece of metal built into the top of the processor, to transfer heat to the CPU cooler.

Good thermal paste can have a profound impact on your performance because it will allow your processor to transfer more of its waste heat to your cooler, keeping your processor running cool. Choosing the best thermal paste is also important if you plan on overclocking your rig to its fullest. Even the best CPUs for gaming can often hit slightly higher CPU overclocks if paired with a good thermal paste.

Performance enthusiasts often swear by a favorite brand of paste, but new recipes crop up fairly frequently. We've extensively tested some of the top thermal pastes on the market. If you're hunting for more exotic pastes off the beaten path, we also have plenty of historical data below covering 90 different pastes (and yes, we've even tested toothpaste).

Thermal paste can go by many names, such as "thermal compound," "thermal grease," or "TIM" (Thermal Interface Material), but they all have the same purpose — to help keep your chip cool by ensuring that heat passes efficiently from the CPU to the cooler.

We’ve also tested Phase Change compounds. These types of products begin as a solid, and are installed in the same manner as a thermal pad. However, once exposed to heat and pressure, they liquify. The primary downside to this type of material is that it can have a longer burn-in time, and it may not perform as well as pastes in lower power scenarios.

Even though a dizzying array of different thermal pastes is available — some blends have been around for over a decade — new formulations still come to market at a surprising pace. Our testing includes many newly released thermal compounds, as well as tried and true brands of thermal paste.

Lastly, we’ve also tested thermal pads and sheets. These pads can be used as TIM and come as a single sheet you simply apply to your heatsink, but they’re not all made the same. There are some rather interesting non-traditional thermal pads that have entered the market recently, like Thermal Grizzly’s Kryosheet, which is made of graphene rather than the silicone-based pads typically used.

Here are the best thermal pastes, along with our complete test results. Remember that you don't always get what you pay for, as some budget pastes come awfully close to or overtake their more expensive competitors.

Prime Day Exceptional Thermal Paste Deals

Here are a few standout deals from the Prime Day event, which is currently taking place. Our list of best overall picks continues below.

Best Thermal Paste for CPUs You Can Buy

Best Premium Paste

Best Premium Paste

Thermal Grizzly’s Duronaut is the best performing thermal paste we’ve tested, hands down. In addition to its excellent thermal performance, it is designed specifically for long-term stability. Its only downside is that it is more expensive than competitors - but that’s worth spending a few extra bucks!

Runner Up: Best Premium Paste

Runner Up: Best Premium Paste

Arctic’s MX-6 is a favorite among PC enthusiasts, and it's easy to see why, given its excellent thermal results - currently holding the 2nd best spot for traditional thermal pastes in our benchmarks.

Best Premium (Standard) Thermal Paste

Best Premium (Standard) Thermal Paste

ID-Cooling’s Frost X45 is the best-performing thermal paste we’ve tested on our air cooling system, hands down. It’s available for only $6.99 on Amazon, so it’s the hands-down winner if you’re focused on value.

Runner Up: Best Premium (Standard) Paste

Runner Up: Best Premium (Standard) Paste

While many of Noctua’s products carry premium price tags, like the NH-D15 G2 Air Cooler, when it comes to thermal pastes, Noctua’s NT-H2 carries a relatively “budget” price tag of only $12.95 for a 3.5G tube that also includes three cleaning wipes.

Best Premium Thermal Pad

Best Premium Thermal Pad

Thermal Grizzly’s Kryosheet has - thus far - been the best thermal pad we’ve tested. Not only that, but in our testing on AMD’s Ryzen 9 9950X it outperformed all traditional thermal pastes. Its only downside is that it is more expensive than most pastes, but it has the advantage of being reusable.

Runner Up: Best Premium Thermal Pad

Runner Up: Best Premium

Thermal Grizzly’s PhaseSheet is a PTM-type phase change compound - a solid which melts under high pressure. This has the advantage of being reusable. Don’t be alarmed if your CPU reaches peak temperature when you’ve first applied this product. The downside of PTM is that it requires extensive burn-in time with multiple cycles before it performs at optimal levels.

Best Liquid Metal Thermal Paste

Best Liquid Metal Thermal Paste

Alphacool’s Eisfrost Extreme was the best-performing liquid metal we’ve tested, outperforming competitors by a significant (for liquid metal) 0.5C degrees! If you’re looking for the best performance on the market, bar none, you’ll want to pick up Eisfrost Extreme.

Runner Up: Best Liquid Metal Thermal Paste

Runner Up: Best Liquid Metal Thermal Paste

BeQuiet’s DC2 Pro is on par with Thermal Grizzly’s Conductonaut overall but is available for much less. As with all liquid metal compounds, extra care will be needed during installation due to electrical conductivity.

Thermal Paste Performance Rankings

Thermal Paste Performance Rankings

Here's a breakdown of our recent testing, and we'll be adding new pastes to this list over the coming weeks and months. A bit further down, you'll find our original rounds of testing with 85 different pastes tested in 2017 and 90 pastes tested in 2022, some of which we've revisited in this new performance hierarchy. That should give you a good idea of how other pastes that we haven't retested yet would compare to the newer pastes.

First up, here’s our newest testing with 37 pastes on the Ryzen 9 9950X test system. You can expect this list to grow to include all of our pastes.

Here’s our testing of 90 different pastes from earlier this year with the Core i9-14900K system. We tested these pastes with both air and liquid cooling, but we’re moving forward with the simplified AIO-cooling test methodology used in the prior results. We’ll retire this down to our archives at the bottom of this article once our new test system has a sufficient number of results.

Thermal Paste Test Results

Thermal Paste Test Results

▶️ Key Takeaways

Thermal compounds might always be compared and debated over, but the simple fact remains: PC system building needs thermal compounds to effectively dissipate thermal loads. Without them, our beloved gaming and content-producing machines would struggle to keep components cool during heated frag sessions, heavy workstation computations, or just simply browsing the web.

Not every system will need the most expensive compound, so even the most budget-minded system builders can rest easy knowing that even lower-cost pastes can still prove very effective. You can see our historical testing results with far more pastes after the test setup.

Test System Configuration and Testing Methods

Test System Configuration and Testing Methods

For our thermal compound tests, I used the same hardware and configuration for each and every test to minimize environment variables in our testing. Some of these components were sampled by vendors, without whom this testing wouldn’t be possible. We’re using Ryzen 9 9950X paired with Arctic’s Liquid Freezer III Pro AIO and an ASUS ROG Strix B850-E Gaming Wifi motherboard. We’d like to take a quick moment to thank our partners at MSI, Arctic, ASUS, and AMD for sampling the components used for this testing.

While most thermal compounds scale similarly with AMD and Intel CPUs, I feel I should point out there were a few notable exceptions to this rule: the most impressive being Thermal Grizzly’s Kryosheet, which outperformed all traditional thermal pastes on our AMD Ryzen 9950X.

Each compound is properly burned in before testing, with a burn-in period appropriate to the compound being tested. Most paste applications are burned in with 30 minutes of Cinebench R23 Multi-core testing, split between two 15-minute tests with a cool-down period afterward. There are some exceptions to this rule. With phase change materials like Honeywell’s PTM7950, I ran Cinebench for four or more 30-minute tests with cool-down periods in between. With Liquid Metal (LM) materials, only a single burn-in test for 15 minutes was needed, as LM doesn’t really require a burn-in period at all.

To test each thermal compound, I ran Cinebench R23’s multi-core stress test for 15 minutes after each compound had been burned in. This is a long enough thermal load that most pastes will reach their maximum temperature by the end of the benchmark. I measured the average temperature of the CPU during testing to demonstrate the effectiveness of a thermal compound.

The reason I use the average temperature instead of the peak temperature is consistency: I observed more variation with peak temperature results than I was comfortable with, but the average temperature results recorded were very consistent.

Excluding results that were thrown out and retested with a different tube of thermal paste, most verification results had a variance of no more than 0.3C. I’d prefer to reduce that variance to 0.1C or less - but there’s only so much one can do to eliminate variance without having an expensive custom testing lab.

There are a lot of factors that can impact the performance of a paste. How you apply Thermal Paste and mount your cooler are the two biggest factors, but there can also be variations in the quality of different tubes of the same brand and model of thermal paste. We have retested results to ensure accuracy, but we can’t account for all potential variances in product quality. That said, if testing results from one tube were worse than expected, another tube was obtained.

What is Thermal Paste (TIM) made of?

Most pastes are made of ceramic or metallic materials suspended within a proprietary binder, allowing for easy application and spread and simple cleanup. Depending on their specific formula, these thermal pastes can be electrically conductive or non-conductive. Electrically conductive thermal pastes can carry electricity between two points, meaning that if the paste squeezes out onto other components, it can cause damage to motherboards and CPUs when you switch on the power. A single drop out of place can lead to a dead PC, so extra care is imperative.

Liquid metal compounds are almost always electrically conductive, so while these compounds perform better than their paste counterparts, they require more focus and attention during application. They are very hard to remove if you get some in the wrong place, which would fry your system.

In contrast, traditional thermal paste compounds are relatively simple for every experience level. Most, but not all, traditional pastes are electrically non-conductive.

Legacy Thermal Paste Testing

Legacy Thermal Paste Testing - 90 Pastes Tested

Here's our legacy thermal paste testing chart that we generated back in 2022. As you'll notice, many of the same popular pastes in 2022 are still on the market, making it into our new round of testing.

We do have new testing equipment for our updated tests, such as a more modern CPU, motherboard, and coolers for our tests - and we use a different stress test. That means these tests are not quite comparable to our legacy results.

We'll be adding more thermal pastes to our new hierarchy; stay tuned.

▶️ Best Thermal Paste 2017 Legacy Benchmark Results

▶️ Best Thermal Paste 2022 Legacy Benchmark Results

Yesterday on X, Cooler Master opted to show off its latest CryoFuze 5 thermal paste series by using all six available colors to plant a landscape on an existing 13th Gen Intel CPU and Gigabyte Z790 Aorus Master motherboard.

There was some controversy around a machine error translation that made people think the product was named "Cooler Master CryoFuze 5 AI thermal paste" when, in fact, the original text was saying the nano-diamond thermal paste should be good enough for high-power CPUs with onboard NPUs.

The six colors used to create the painting above can also be pictured below in more reasonable pea-shaped sizes. These colors are red, blue, yellow, white, green, and black. And, of course, neither the thermal paste configuration recorded above nor the one pictured below should be considered a practical use case for a single CPU—colored thermal paste, in general, is just a tiny frill on an otherwise standard, near-invisible part of everyday PC building.

While both of the thermal paste configurations highlighted by Cooler Master for its CryoFuze 5 thermal paste are fairly cool-looking (no pun intended), we want to take a moment to remind users of the proper way how to apply thermal paste to your CPU. 

Typically, the proper way to do this is to squeeze out an amount akin to a pea on most CPUs or even multiple "grains of rice" in a grid formation on larger processors. While you need thermal paste or other TIM (thermal interface material) to cover the whole CPU, you also want it to be evenly distributed and a thin layer that transfers heat as directly as possible. Too much or unevenly applied paste can cause thermal issues with your CPU.

Even so, it's still pretty amusing to see Cooler Master take its super high-performance CryoFuze 5 thermal paste and different coloring variations this far. On paper, the thermal paste has what it takes to rival the best thermal pastes on the market, though, of course, it doesn't compare to something like liquid metal TIM (though using that comes with much heavier risks than standard thermal paste).

Thermal Grizzly has introduced a new thermal pad product for cooling CPUs and GPUs. Known as PhaseSheet PTM, the new pad uses phase-changing technology and is electrically nonconductive.

As the name implies, the new PhaseSheet PTM takes advantage of a phase-changing material that changes its physical properties depending on temperature. At room temperature, the sheet is solid (just like any ordinary thermal pad). Still, at temperatures above 113 degrees Fahrenheit (45 degrees Celsius), the thermal pad turns into a very low-viscosity liquid that behaves similarly to the thermal paste.

The phase-changing tech is designed to minimize the pump-out effects of traditional thermal paste. Pump-out is an effect where the thermal paste is slowly pressed out between a heatsink and a GPU die or CPU IHS due to micro expansions and contractions in the metal that occur in the heatsink contact plate or CPU IHS; the effect can reduce cooling performance over a lengthy period.

Thermal Grizzly's Phaseheet PTM is much less susceptible to pump-out, giving it a long service life. Additionally, the thermal pad is reusable and non-electrically conductive, so it can be used safely on components that don't have an IHS, such as mobile CPUs and GPUs. This starkly contrasts Thermal Grizzly's Kryosheet thermal pads, which are electrically conductive and can be damaged easily if re-used.

The Phaseheet PTM requires 300 to 400 newtons (67 to 90 pounds) of pressure to be used optimally with the lowest possible layer thickness (i.e., best performance). Once deployed, the thermal pad develops and stabilizes its maximum thermal conductivity after around ten cycles above 60C. Thermal Grizzly is selling one size of the Phaseheet PTM, 50 x 40mm, which costs $10.59 for one pad.

Thermal pads like PhaseSheet have several advantages over traditional thermal paste. Their solid nature makes them very easy to replace if required and enables them to last long without succumbing to pump-out losses.

Clock Work Tea Party (CWTP), known for its apple-scented thermal paste, just launched its ‘Ekusu and Mugeru’ thermal paste, which comes with its own dedicated gun. This applicator gun looks similar to the silicon sealant applicator guns you can buy at your local hardware store, but it is for applying a new type of thermal gel to your PC build.

The CWTP Special Gun is designed to fill in the gaps of uneven heat-generating elements and conduct heat, thus replacing the thermal pads typically used to cool GPU memory or VRMs that become hot during prolonged use. Unlike thermal pads, the gel will squeeze into the gaps between the components, perhaps providing a bit of extra coverage. The applicator gun makes applying thermal gel much more efficient but perhaps not as precise—it looks pretty easy to overdo it.

One thermal gel container weighs about 30 grams and should be enough for one (or three) PC builds. The thermal gel is also pink, not the usual gray, giving it additional style points. Given its use case, it's safe to assume the gel isn't electrically conductive like some thermal pastes for CPUs. Nevertheless, you likely won’t see the color of your thermal gel once applied, so you're free to get a bit messy.

CWTP is known for its eccentric thermal paste solutions, like its strawberry and ‘flowers from heaven’ thermal paste. This thermal paste package costs 5,280 yen or about $34.43, which might be a bit pricey, but considering that it weighs ten times more than the average thermal paste you can get on Amazon, you might get a lot of value out of one tube.

We haven’t seen any specifications for this particular thermal gel, but judging by the performance of the brand’s previous offerings, it looks like it will work decently.

Despite the addition of the applicator gun, thermal pads, like those from Gelid and Thermalright, are still much more user-friendly as they’re easier to apply and more consistent than thermal goop. But, at the very least, the Ekusu and Mugeru thermal paste with applicator gun will make it feel like you’re working in construction while building your PC. We'll try to source the thermal gel and see if it's good enough to merit a spot among the 90 other contenders on our list of best thermal pastes. 

Cooler Master released an official statement on X saying that its latest product, the Cryofuze 5, is not ‘AI thermal paste’. The term came from a Google-translation of the Chinese page for the Cryofuze 5, where the original Chinese characters — AI竞彩导热膏 — were translated as ‘AI competitive thermal paste’ or ‘AI thermal paste’.

The official statement from Cooler Master says that the company isn’t actively promoting the Cryofuze 5 as an ‘AI thermal paste’ in the sense that it uses AI to help transfer heat from your CPU or GPU to the water block or heat sink. Instead, the original term meant to say that the Cryofuze 5 is perfect for AI-enabled chips, especially as these could generate more heat.

As we have previously reported we thought that Cooler Master’s new thermal paste was designed for high power AI applications, like Intel’s 1500-watt TDP Falcon Shores and Nvidia’s B100 and B200 GPUs that could reach 1000 watts. This was especially true with the company’s claimed stability for the thermal paste from -50 to 240 degrees Celsius — meaning the Cryofuze 5 will perform as expected even if you use liquid nitrogen to cool your PC, like how this M4 iPad Pro was cooled.

Cooler Master shows that it isn’t just capitalizing on the AI trend by slapping "AI" to its new products. Instead, the company made the Cryofuze 5 to help PC builders get ready for even hotter CPUs, APUs, and GPUs, especially as AI powered processors are now slowly becoming available to the PC building community.

The ‘AI Thermal Paste’ was talked about for a short while, especially as many people pondered on the meaning or significance of ‘AI Thermal Paste’. This statement clarifies the air and shows that it was all a misunderstanding.

Nevertheless, the few days in which we all pondered ‘AI Thermal Paste’ is a marketing win for the company, as the efforts of its marketing team reached more people and ‘AI thermal paste’ became a minor meme because of this harmless snafu. At the very least, Cooler Master achieved what it wrote on it’s X bio—“Your #1 go-to for the coolest PC hardware memes!”

Cooler Master just released a new line of CryoFuze 5 'AI Thermal Paste' that comes in six different colors. The company uses zinc oxide and aluminum powder to make the colorful thermal paste, while also claiming that it uses 'nano-molecular technology' to deliver stable performance.

While the added colors are likely just a gimmick or for creators filming their PC builds, the bigger claim here is the thermal paste’s performance and stability across a wide range of temperatures. According to the CryoFuze 5 China product page, the thermal paste has a thermal conductivity coefficient of 12.6 W/mK, giving it better performance than all other thermal pastes we’ve tested in our Best Thermal Paste for 2024 guide, save for the SYY 157 that has a rating of 15.7 W/mK. It won't match the values you can get from liquid metal thermal pastes, however, which offer thermal conductivity ratings of 73 W/mK or higher.

Cooler Master uses the AI branding on CryoFuze 5, but there is nothing AI about a thermal paste solution. While perhaps Cooler Master could've designed it for AI processors, especially as next-generation AI chips like Intel’s Falcon Shores and Nvidia’s B100 and B200 GPUs have TDPs higher than 1,000 watts, the CryoFuze 5's thermal performance isn’t that far ahead of its competitors.

The CryoFuze 5 might not mean much for the average PC builder. But enthusiasts looking for style points on their video builds might love it (even though no one will ever see it again once the PC is assembled, unless they take the CPU cooler off). This also isn’t the first colored thermal paste from Cooler Master, as it already sells the CryoFuze Violet thermal grease.

More importantly, the CryoFuze 5’s high thermal conductivity (for a thermal paste) allows overclockers to push high-performance silicon even more. This is particularly crucial for builders using more exotic solutions, like using the EKWB AIO liquid-cooler designed for delidded CPUs, or those who replace the stock heat spreader on the processor with a custom one from Thermal Grizzly.

The stability of Cooler Master’s colorful thermal paste adds another advantage, especially for overclockers who aim to get the most out of their silicon. If you’re one of the few who use liquid nitrogen to cool your PC, you'll appreciate the CryoFuze 5's ability to work from -50C to 240C.

Liquid metal should still perform better than the CryoFuze 5, but it comes with the added risk of shorting components as it's a conductive material. While the color options and AI branding are likely just for marketing purposes, its improved performance should help enthusiasts looking to redline their systems.

Thermal paste maker Clock Work Tea Party (CWTP), known for releasing scented non-conductive thermal pastes, has now released an osmanthus-scented variation in limited quantities. The thermal paste will be ready for purchase on April 12 and available in Japan with a worldwide shipping option.

There's no explanation given why CWTP makes scented thermal pastes or if it includes specific unique properties that make one's system smell nice at higher temperatures. The scent is extracted from Osmanthus fruit and mixed with the base ingredients containing Silicone and metal oxide. However, the product comes with a commemorative resin card for this limited version.

Based on its specs, CWTP rates itself as having a high durability grade and reasonably good ease of application. The thermal paste works in environments between -50 degrees Celsius and 250 degrees Celsius. CWTP recommends this paste for liquid and air coolers, with a soft viscosity that allows easy spread over the CPU's integrated heatsink. The company assures its high durability, which makes it more suited for long-term applications.

Despite multiple options, choosing a thermal paste is relatively easy, given that little one could go wrong with choosing a widely available and community-chosen thermal paste. CWTP does have non-scented variants but makes limited quantities of scented versions. The green apple-scented paste was the first to gain attention worldwide, and the previous version smelled like strawberries.

We tested a plethora of readily available thermal pastes a few months ago, so it would be interesting to see how CWPT's option holds itself against the recommended ones. Even with the oversaturation of choices, it will be interesting to know if the locals prefer to pick this up, given that thermal pastes typically stay with an average single-PC user for a few years, more if the applied thermal paste has higher durability. Due to advancements made with thermal pastes, single-application alternatives like Gelid and Thermalright are more user-friendly as they have much higher consistency than spread thermal paste.

Who knows, maybe someone will make a thermal paste that would discourage an ant infestation, which would be more beneficial than a scented thermal paste.

Many readers will have battled ant infestations in their yard or home – but these tiny insects can take over our PCs, too. Redditor Thejus Parol recently noticed that his graphics card temperatures had been rising inexplicably, and it didn’t take long to find a likely culprit – ants (h/t PCGamesN). According to Parol’s initial investigations, the ants had been “eating the thermal pads and thermal paste” in his GTX 1060 GPU inside his PC. This would account for degraded thermal performance if done to a drastic extent, but even though the visual evidence does suggest some damage to the thermal pads, it doesn’t sound entirely plausible that the ants had that much of an impact. Let’s take a closer look.

Some blame climate change, but whatever the cause, destructive and stinging fire ants are moving north. The worker ants of this invasive species are quite tiny, and like other ants, they appear to be attracted to electric fields. Thus, a warm humming PC with its nooks and crannies and multiple powered components might prove to be an irresistible target for investigation, or even colonizing.

Ants are eating my gpu from r/pcmasterrace

Though his system and GPU fans were still running as expected, Parol’s eye was caught by ants marching across the top of the PC case and inside, over the graphics card. Determined to see what was attracting the ants, the Redditor partially disassembled the PC and GPU and found that the suspected Solenopsis invicta were consuming thermal pads and thermal paste. You can see damage to the pads clearly in the second image in the above album.

A thorough system cleanup with IPA (ethyl alcohol) and a fresh thermal paste application seemed to get things back to normal for Parol. Further precautions were taken by spraying the desk and surrounding area with insect repellant. However, “another set of ants appeared in the exact same place, doing the exact same thing, eating my GPU alive,” noted the anguished PC enthusiast. Other Redditors have been quick to help identify the issue, highlight possible solutions, and share their own stories of PC ant attacks.

I have also experienced fire ants in a laptop, which took quite some time to clear. As well as the potential for these insects to sting and infest places like food cupboards (especially where sweets are stored), ants can damage electronics – causing short circuits and even starting fires.

Moving on to whether the ants are “eating” things like thermal pads or paste – this appears to be highly unlikely, but there have been scattered results of this occurring in the past. Nevertheless, in a PC full of hard metal, plastic, and other inedible components, the ants could also be pulling the relatively soft thermal pad and paste material to pieces as they scout the area.

Searching the depths of the internet reveals that this is far from the first time that ants have invaded PCs or Macs. Moreover, similar suspicions regarding ants eating thermal pads or paste have been raised previously. Below you can see another example, this one from a video posted three years ago about a similar problem. 

My CPU/GPU got infested by ants when I was gone for a month. I played games and ran benchmarks so they would come out cos of heat. Also left my pc running overnight but they still inside. Help from r/pcmasterrace

As is often the case for PC ownership, doing some research, being determined, and being vigilant is the best course of action when facing an issue, and this applies to those who think ants might be looking to make a home in their machines. If ants affect other things in and around your home, it might be best to call a professional exterminator. Others might prevail against the army of ants by targeting suspected nests with over-the-counter ant poison, traps, and other domestic anti-ant tactics.

Keeping up with a similar themed thermal paste Mining Co. Ltd released a couple of months ago, the company announced its newer strawberry-scented 'Extreme Mugurisu CWTP-EG4G' non-conductive thermal paste in Japan. The Hiroshima-based company is making these in collaboration with CWTP (Clock Work Tea Party) for 980 yen for a 4g syringe, roughly translating to US$ 6.60. The color of the paste is also made to look pale pink.

This thermal paste is marketed as a 'torque type,' engineered for gradual thermal transitions. It does not explain the whole point of having a fruit-flavored thermal paste, nor does it have any longevity of the smell once applied. One wouldn't know if adding a fragrance would adversely affect its thermal conductivity or lifespan.

CWTP says these thermal pastes can be used for any CPUs, chipsets, memory, etc. It is advertised as a highly durable product whose application can last up to four years when it is new. The Extreme 4G Strawberry has a thermal resistance range of -50 to 220 degrees Celsius, though the image of the package rates this up to 240 degrees. This is where these companies need to be clear about their product specifications, and therefore, one would be more skeptical about the thermal performance claims in their specifications.

Unlike its Apple Edition, CWTP does not display the thermal paste's viscosity, durability, and thermal conductivity in its specs. Instead, it only shows a 'stage index' that doesn't help. The packaging of this thermal paste displays similar specs but with lower thermal resistance.

Earlier, we reported that the Apple version was also advertised to have 12.8 W/mk thermal resistance. Hence, the base mix of this thermal paste will likely be the same, with the company simply adding fragrance whenever it releases a scented version. Unlike the apple variant, the strawberry version is advertised to use silicone, aluminum oxide, zinc oxide, carbon, and naturally derived fragrances (strawberry in this thermal paste). The paste is made in China, according to the packaging label.

This will likely be available only in Japan, much like its other scented counterparts, though it does offer international shipping. Sure, there could be someone who has a thermal paste collection likely to purchase this. Still, realistically, the shipping cost and the customs duty would make others look at more comprehensive options. One might be curious if it would smell nice under higher thermal conductivity. Who knows! Maybe the next flavor would be of a local delicacy sold worldwide.

A disclaimer is implied without saying that this is not meant to be consumed. Since there's no guarantee it will smell nice when the CPU is on load, it may not mask any naturally derived lousy smell, let alone cigarettes.

A syringe of ancient thermal paste has been tested by Igor’s Lab. With some surprise, the hardware testing stalwart reports that Arctic Cooling’s Silicone Paste worked just as well as a factory fresh industrial alternative with a similar formulation. However, Wallossek’s testing clarified that modern PC thermal pastes aimed at PC enthusiasts perform much better.

A PC hardware dealer in Germany discovered some 20-year-old thermal paste at the back of a drawer and decided to send it to Igor’s Lab. Wallossek looked at the Intel Pentium 4-era paste from Arctic Cooling and thought it was like finding an old can of soup – but one that “can’t spoil.” Without much hesitation, testing began.

The initial finding was that, since the syringe had a good seal, the paste squeezed out as it should, with an acceptable consistency.

The ingredients also piqued Wallossek’s interest. According to the packaging, Arctic Cooling's old Silicone Paste featured 50% silicone, 20% carbon, and 30% metal oxide. This required verification, decided the veteran hardware tester and ex-Tom’s Hardware writer. So, he employed a laser-induced breakdown spectroscopy device to analyze the paste’s ingredients. Wallossek reckons that the ingredients on the label were bunk, as the analysis tool reported the paste was made from 50% silicone and 50% zinc oxide. He concluded the mention of carbon on the packaging was solely for marketing purposes…

Moving onto the comparison testing, Igor’s Lab noted that a TCTG-4.0 from MCT, an industrial “durability-focused reference paste,” performs very similarly to the antique Arctic Cooling paste. This indicates that little, if any, degradation occurred during the old paste’s slumber at the back of the PC hardware dealer’s drawer.

The Pentium 4 era paste significantly underperformed compared to a modern thermal paste, though. Wallossek tested an Intel Core i9-13900K with both the old Arctic paste and the “modern, good” Alphacool Apex thermal paste. The graph of the comparative test run (below) shows a delta of six degrees Celsius, representing 20 years of progress in thermal paste formulation. It's not astonishing, but a very welcome improvement.

From the above tale, we might conclude that thermal paste packaging that features ‘use by’ or ‘best before’ advice from manufacturers might be wise to ignore.  This may only apply if the paste is kept well, like in a sealed tube in a dark, cool drawer.  I just checked my drawer and found three partly-used thermal paste syringes, and none of them seemed to have any ‘use by’ date indicated on the packaging.

For more thermal paste comparisons, look at our colossal roundup in our Best Thermal Paste for CPUs 2023: 90 Pastes Tested and Ranked feature.

Hong Kong-based PC cases and cooling specialist Gelid has launched a new thermal pad product dubbed HeatPhase Ultra. As hinted at by the name, the company claims this thermal pad uses a phase-change material and offers the ultimate in thermal transfer efficiency between a processor and cooling block. Gelid has a lot of big claims for its HeatPhase Ultra, which it says is easier to apply, offers improved durability, and delivers better performance than traditional thermal pastes. 

It's difficult to understand how the HeatPhase Ultra thermal pad we see in the product images is a phase change material (PCM). According to our normal understanding of a PCM, it enjoys a very high latent heat capacity, which is absorbed or released when the material’s phase changes. A phase change might be from gas to liquid, from liquid to solid, or vice versa. How that works with this quite normal-looking pad, which claims to be “ultra-durable and non-curing… [and] no-bleeding,” is difficult to fathom from the product pages alone.

Moving along to other claims by Gelid, there's the HeatPhase Ultra's performance. Gelid has provided a performance chart, embedded below, which it says shows how well the HeatPhase Ultra thermal pad performs in direct comparison to a traditional thermal pad, and Gelid’s own GC Extreme thermal paste.

We have some experience with GC Extreme and it was the runner-up in the hotly contested best budget thermal paste category in our Best Thermal Paste for CPUs 2023 feature, which assessed 90 pastes.

In Gelid's testing with an AMD 7950X, the HeatPhase Ultra pad kept the CPU about 2 degrees Celsius cooler under load compared to GC Extreme paste (79 degrees Celsius). We think those results are actually very close and probably within the margin of error, but if HeatPhase Ultra is instead just an equal performer to GC Extreme, it is still a very valid alternative for the reasons outlined below.

Thermal pads can have inherent properties that are preferable to pastes. Gelid says the HeatPhase Ultra is effortless to apply or remove. Some images show a protective film being removed once the pad is in place on the cooler heatsink. Other thermal pad niceties such as a guaranteed evenness of application remain true here. Gelid also claims its new product is ultra-durable, with a long life during which it won’t cure, harden, or otherwise degrade. Moreover, the non-electrical conductive material is said to stay in place without spreading under pressure.

Gelid is now selling HeatPhase Ultra thermal pads pre-cut for modern Intel or AMD processors. In the table above you can see the pad dimensions for either CPU brand. The AMD pad costs $10, and the slightly smaller Intel pad is $9.50. It seems like you only get one pad for the price, but we’d still like to give this a test in the labs and see how it stacks up.

A new limited edition apple-scented thermal paste was launched in Japan today. A collaborative effort between M1N1ing and Clock Work Tea Party, the Extreme Muglis 4G Apple Edition EG4GAP paste is formulated for room-temperature overclocking antics. No, this isn’t designed for Apple's Mac computers, it just reportedly smells like an Apple and comes in green.

The thermal paste was first reported by Japanese publication Hermitage Akihabara. While it doesn't offer a reasoning for the scent, the idea behind the suitably apple green color is that it contrasts better with the silver metal IHS which caps a processor, making it easier to ensure even and complete coverage. “Painting” a CPU isn’t our recommended method of applying thermal paste, so the color coverage explanation doesn’t really work for us.

Clock Work Tea Party EG4GAP is a special edition release of the seemingly popular CWTP-EG4G thermal paste (it’s out of stock). Apart from the scent and color, the pastes appear to have the same specifications:

In some supplemental information about the quality of the new CWTP-EG4GAP paste, it is described as using extremely fine particles precipitated using ultrasonic technologies. Considering the specs, its 12.8 W/mk thermal conductivity is a smidgeon better than the well-regarded Thermal Grizzly Kryonaut. However, we can’t say anything about the actual performance, ease of use, or cleanup of EG4GAP, without some testing time.

The Extreme Muglis 4G Apple Edition EG4GAP paste is going to be a limited release of 1,000 syringes. It thus might be difficult to get a review sample for our extensive best thermal pastes roundup. At the time of writing the product page doesn’t load, but sales are supposed to go live from November 24. The retail price is said to be 980 Yen, which is about $6.50.

Just remember, don't ingest any thermal paste, regardless of whether or not it smells like food.

A Korean tech site has investigated and ranked 17 thermal-paste alternatives. Quasar Zone chose a collection of likely-looking household items and discovered that an antibiotic ointment and a ‘love gel’ were top contenders, but BBQ sauce was no better than a bare heatsink.

PC builders, DIYers, and tinkerers may sometimes have to improvise when the situation demands it. A common tech staple that gets used up and not replenished is thermal paste, sometimes called TIM (Thermal interface material). Stuck in this situation, you might be lucky enough to discover some old paste or pads at the back of a drawer, or you might even live near a computer store. Others will naturally start to wonder if anything else in the garage, medicine cabinet, or kitchen cupboards will suffice.

Quasar Zone used Zalman ZM-STG2M as its reference point. Using this TIM, in a system that mixed an Intel Core i9-12900K running at “full-load” for 10 minutes, the commercial Zalman paste and DeepCool AK620 cooler kept the CPU at under 80 degrees Celsius. An average of 79.11 degrees Celsius was observed with this sensible combination, to be exact.

The two most successful TIM alternatives managed very similar performance, just a degree or so higher than the Zalman. The best alternative, if you have it at hand, is a Fucidin ointment (see images above). This is an antibiotic cream for various skin issues.

Very closely behind the ointment was a ‘Love Gel.’ This clear and slippy gel was difficult to apply and see on the heatspreader (image above). However, its score is very close to the purposely formulated Zalman paste and the Fucidin cream.

Some other alternatives that weren’t terrible in the test included tomato ketchup, hand cream, and sunblock. The application of most of these very common items resulted in an average CPU temperature of about 83 degrees Celsius during the tests.

Quasar Zone tested four notably bad thermal paste alternatives, which weren’t any better than no paste at all, as they all “failed” the test with temperatures over 95 degrees Celsius. Vaseline’s bad performance among these was so unexpected that it was re-tested, only to fail again.

So, we seem to have a handy indicative list of household items that we could use for thermal paste “in an emergency.” However, it must be noted that precautions need to be observed. For example, some of these products might be electrically conductive and cause damage if they get elsewhere in your computer. Other TIM alternatives might boil and cook or otherwise change their form after prolonged heating. For example, the Fucdin ointment deposited a “black band” after its spell as a TIM. Perhaps the best performers now need longer-term tests for integrity/stability.

Now might be a good time to check your own supply of TIM. If you think it might be a good idea to stock up, please check out our extensive guide to thermal pastes with 90 alternatives ranked, including denture adhesive and toothpaste.

A Chinese TechTuber has revealed how Asus has managed to cool the powerful new AMD Ryzen 9 7945HX3D for laptops, as well as the GeForce RTX 4090 Laptop GPU. Bilibili user Ordinary Uncle Tony disassembled his Asus ROG Strix Scar to quite a daring degree to reveal the AMD APU as shown above and below (h/t HXL).

What you see is AMD’s powerful X3D enhanced mobile APU — without an IHS, of course — with its multiple dies visible. Solder mask, or a similar non-conductive barrier like a lacquer or epoxy resin, has been meticulously applied to the protect the processor circuitry surrounding the dies from the damage which might occur from stray drips and drops of (electrically conductive) liquid metal.

PC enthusiasts will be aware that liquid metal is coveted for its great thermal properties when used as a TIM (Thermal Interface Material), but it has some particular drawbacks.

On desktop processors with liquid metal TIM, the application placement and maintenance of the metallic goo is still tricky, but it can be constrained more simply with a uniformly shaped barrier, stopping it from flowing to areas it should not be.

Asus has been applying liquid metal to high-end laptop processors for several generations now. Before its first commercial laptop use in 2019, Asus says it took two years to experiment with production line application of the conductive but messy liquid. Asus “added a tiny barrier sponge just 0.1mm tall around the CPU socket, safeguarding against any accidental seepage.” This spongy method seems to have become redundant with the X3D mobile processor.

If it applied liquid metal to the AMD Ryzen 9 7945HX3D, it would have been first time Asus has had to cope with the complications of a multi-tile processor. With the exposed dies and electronic components on a mobile chip like the Ryzen 9 7945HX3D, some more complicated TIM wrangling would be called for.

We see that the red solder mask (or similar lacquer coating) is one effective method of mitigating the presence of potentially hazardous room-temperature liquid metallic material. Solder mask is a simple, non-conductive durable barrier that has been used in electronics applications for decades. We wonder if it too is being applied by robots on the production line. Anyway, this application seems to have only been done to protect the X3D APU from liquid metal contamination from the GPU. It looks like the AMD APU contacts with the large vapor chamber cooler via a thermal pad.

In our review of the Asus ROG Strix Scar 17 X3D, we noted the massive cooler and vapor chamber for the CPU and GPU. The hottest area of the system was recorded 56.6 degrees Celsius (133.88 F) on its underside. However, the thermal imagery indicated that the cooling was effective in taking the heat away from the processors and expelling most of it out the back. No evidence of thermal throttling was observed in the demanding benchmark runs.

When we mention Thermalright, we think of high-performance air or liquid cooling systems as well as accessories for DIY PCs and, therefore, products aimed at enthusiasts. But it looks like even Thermalright wants to address a more mainstream market, which is why this week it quietly unveiled its first thermal pads, as FanlessTech noticed.

While thermal pads often offer lower thermal conductivity and performance than the best thermal paste, Thermalright rates the thermal conductivity of its Heilos pads at 8.5W/mK, and thermal resistance at 0.04°C cm2/W. To put the numbers into context, the thermal conductivity of Arctic's MX-4/MX-5 is also spec'd at 8.5W/mK, and this is considered to be a quite decent level of performance for inexpensive pastes, as far as our list of the best thermal pastes goes. 

Thermalright offers two types of Heilos thermal pads: one measuring 40x40 mm for AMD's AM5 CPUs and another measuring 40x30 for Intel's LGA1700 processors. Both thermal pads are 0.2 mm thick.

Applying thermal paste optimally could be challenging for novices in DIY PC building, so specialists from Thermalright thought that advanced thermal pads could be a viable option for them. While thermal pads tend to offer lower performance than the best thermal pastes, which are usually designed for overclocking and tailored for particular types of cooling systems (air, liquid, liquid nitrogen, etc.), they are easy to use. Furthermore, Thermalright's Helios promises performance that is akin to good mainstream thermal pastes, so for DIY PC rookies, they might be just what the doctor ordered.

Changes to the shape, size, and internal component layout of modern CPUs have made applying thermal paste, also known as thermal interface material (TIM), more complicated than it used to be.

CPUs have incorporated ever more cores and core types. Chiplets and hybrid architectures have proliferated, moving the most thermally demanding bits away from the exact center of the integrated heat spreader / lid of the CPU. And despite shrinking manufacturing nodes, many processors have just gotten physically bigger. So while you used to be able to apply thermal paste basically the same way across all consumer manufacturers and platforms and expect great results, that's no longer the case.

And let's face it: There was never any true consensus across the PC-building world about exactly what is the "right" or "best" way of applying TIM is. We all just know the wrong way when we see it. So at the risk of verging into an area of hotly contested debate, we're here to offer some simple instructions on how to properly apply your thermal interface material of choice (check our tested list of the best thermal paste) between your CPU and cooler, to achieve good thermal transfer and get that pesky heat away from your components and outside your case.

We're not saying the advice below is the absolute best method or the only correct method. We're just saying it works, and it's more or less what's recommended by PC thermal experts like Noctua and others.

Oh, and this guide is strictly for traditional thermal pastes – the non-conductive, viscous materials that make up the bulk of our best thermal paste list. Liquid Metal compounds can result in lower temperatures than most thermal pastes, but they are also usually conductive, meaning getting a drop or two in the wrong place can fry your components. And if you do get it in the wrong place, liquid metal is often much harder to remove than thermal paste – and you will need to remove it if it gets on your motherboard or other electrical components. As such, we only recommend liquid metal to seasoned PC build experts and serious overclockers.

First, install your CPU

For most of us, it goes without saying that the CPU needs to be installed in your motherboard socket before you apply your paste. But hey, everyone was new at PC building at some point. If we want to keep our hobby (and in our case, our careers) thriving, we need to be welcoming to those who are just attempting to grasp the basics.

So yes, check out our how-to on how to install a CPU if you need it. Get your CPU properly latched into its socket. And, if you're installing an AIO liquid cooler, you probably also want to install your motherboard in the case first (along with any required backplate or mounting hardware).

Because while it's often a smart move to install your CPU and an air cooler with the motherboard outside the case, you'll almost always want to install an AIO onto your CPU after the motherboard is in the case. Having to move your motherboard around while it has a big, floppy, potentially component-damaging radiator attached to it is just asking for a hardware catastrophe.

OK. So your CPU is installed and you've sorted out and installed all the necessary cooler mounting hardware for your CPU / motherboard socket? Good. It's finally time to break out the thermal paste. Unless it's already pre-installed for you.

Want the simplest solution? Get a cooler with thermal paste pre-applied.

Lots of coolers these days, particularly all-in-one (AIO) liquid coolers, come with thermal paste pre-applied to the cooling plate. The image above comes from Corsair's iCUE H100i Elite Capellix XT. This is applied with a machine in a way that assures even application and should work fine for any CPU platform that the cooler supports. After all, no company selling CPU coolers is likely to set its product up for failure by shipping poorly applied (or poorly performing) thermal paste.

So, if you just want to make things easy and aren't going to obsess about getting and maintaining the lowest possible temperatures or the highest possible overclocks, using thermal paste that's pre-applied from the manufacturer is perfectly fine. Just be sure to remember to remove the plastic film or cover that's there to protect the paste during shipment!

And, if at any point you remove the cooler after installing it on your CPU, you'll need to carefully wipe off the pre-applied paste from the cooler and your CPU and apply fresh paste. So if you're upgrading your CPU, or your cooler didn't come with pre-applied thermal paste, we'll see you in the next section, where we finally get to the "how to" bit.

How to apply thermal paste on an Intel CPU (LGA1700, LGA1851)

Intel's previous-generation mainstream CPUs had a square, more compact shape. But with the rise of the hybrid CPU architectures used in 12th Gen Intel CPUs and later, that use the LGA1700 or LGA1851 socket, they have a rectangular shape with more surface area. This, combined with larger, more complex layout of the components under the heat spreader, means that you'll want to apply more than a single dot in the center of the CPU.

For 12th - 14th Gen Intel processors as well as Core Ultra (Arrow Lake), apply one small (3-4mm) dot of paste in the center of the CPU and four smaller dots (2mm) a couple of millimeters in from each corner. Note that the typical syringe applicator and viscosity of thermal paste makes it pretty hard to be exact here. So long as you're not applying substantially larger dots here, you should be fine. It's also pretty difficult with most pastes to apply a dollop that's less than 2mm. Take your time, attempt to replicate something like the image above, and things should turn out fine. Again, just don't go overboard on the amount of paste.

How to apply thermal paste on an AMD CPU (AM5)

AMD's current AM5 socket and its Ryzen 7000-9000 processors are thicker and heavier than their AM4 predecessors. But because the heat spreader has two cutouts around each edge, its surface area for heat transfer is fairly small. So for AMD's Ryzen 7000, 8000, and 9000 CPUs, apply one 3-4mm dot in the center of the CPU.

How to apply thermal paste on an Intel LGA1200 or LGA115x CPU

Older Intel processors have a compact surface area with their primary components in in the center of the chip, under the heat spreader. As such, you should apply one 3-4mm dot on the center of the CPU, just like in the image above of the AMD AM5 CPU.

How to apply thermal paste on an AMD AM4 CPU

AMD's older Ryzen processors on the AM4 socket (Ryzen 1000-5000) straddles the size line between Intel's older LGA1200 socket and previous CPUs and the larger LGA1700 and LGA2066 chips. So either of the above methods (one 3mm dot in the center alone, or one center dot with four smaller dots around the outside) will work just fine. Just be extra careful about not applying too much paste, especially if going for the five-dot method, as socket AM4 CPUs are still quite small.

How to apply thermal paste on AMD TR4 and STRX4 (Threadripper) CPUs

These workstation processors are much larger than their mainstream CPU counterparts (with, generally, many more CPU cores). As such, there is much more surface area to cover for with these chips, which means you'll need more thermal paste in more spots to maintain good thermal transfer.

For AMD Threadripper, apply four 3-4mm dots in a rectangular pattern roughly halfway in from the four corners of the processor. Then apply nine smaller 2mm dots interspersed evenly around and between the four larger dots. In other words, apply three 2mm dots along each of the shorter edges of your Threadripper chip and three more in a line across the center. Once again, it's less important that these 13 dots be exactly this size than it is to make sure you aren't using substantially more thermal paste than this in total.

Next steps

With your thermal paste applied, you're ready to install your cooler. There's no need to spread the paste around, as the metal base of the cooler will do this for you as you mount it. In fact, if you try and spread it manually, there's a good chance you'll spoil the distribution you were aiming for with the dots. Make sure you have all your mounting hardware handy before placing the cooler evenly on the center of your CPU. Then use the latches, pins, or screws of your cooler's mounting hardware to secure the CPU in place.

Once everything else in your system is reconnected and you've booted up for the first time, it's a good idea to run some kind of CPU benchmark while keeping an eye on your temperatures. But if you've followed our thermal paste guidelines above, you should achieve the temperatures and clock speeds that your CPU and cooler pairing are capable of delivering.

Keeping our PC running smoothly is not the most glamorous of tasks, but it is essential to ensure that you’re getting the best from your machine. Replacing your CPU’s thermal interface material (TIM), ideally with the best thermal paste we’ve tested, is one of those mundane tasks that takes just a few minutes. And if your machine has been running hot (or the fans are constantly whirring loudly, which often means the system is toasty), a fresh application of thermal paste can improve performance while dropping your temperatures for improved component longevity. 

You’ll also need to remove and replace your CPU’s thermal paste if you’re upgrading the cooler (perhaps to one of the best CPU coolers) or reusing an old CPU in a new motherboard.

In this how to, we’ll be removing the thermal paste on an old Lenovo M93P Tiny running an I7 4790S. This tiny box lives under a television, providing a Chrome OS Flex desktop in the living room. We need to replace the thermal paste and give it a clean, to assure it’s ready for a few more years of service. However, the steps would be the same if we were doing this with a custom-built PC (see how to build a PC).

How To Replace the Thermal Paste on a CPU

1. Turn on the PC and let it run for a few minutes before shutting down and unplugging. Thermal paste can set hard, and performing a cold pull of the heatsink / cooler can damage the CPU. Alternatively a hot air gun / hair dryer can be used to gently heat the area.

2. Remove the heatsink / cooling assembly from the CPU / GPU. Take your time and loosen the screws to ensure that even pressure is released.

3. Use a little isopropyl alcohol on some lint-free cloth and start by wiping the thermal paste from the heatsink. By cleaning the heatsink first we can test how easily the paste cleans off before we get to the CPU / GPU.

4. Clean the paste from the CPU using isopropyl alcohol and a cloth. Keep the CPU in the socket and gently remove the paste. Don’t be heavy handed and take your time. Any paste in recesses can be cleaned using a cotton swab.

5. Apply the correct amount of thermal paste to the CPU. But first allow the isopropyl alcohol time to evaporate, checking that there are no pools of liquid or debris before applying.

6. Reseat the heatsink / cooling assembly, applying even pressure when placing it on top of the CPU.

7. Screw down the heatsink / cooling assembly by tightening the screws in a diagonal sequence, a few turns at a time. This again keeps pressure relatively even, spreading the thermal paste across the top of the heat spreader/CPU. It also assures there isn’t too much pressure in any one corner, which in a worst-case scenario can physically damage your processor.

8. Power up the PC and use it as normal. Before powering up, be sure to check for any missed screws, trapped wires or misaligned cables. Little “gotchas” happen more often than we care to admit.

Finding the best TIM can be a tricky endeavor, but some people are more adventurous than others. Case in point: An enthusiast recently broadened his GPU thermal paste search to include several interesting substances ranging from regular thermal paste to thermal pads, cheese, ketchup, toothpaste, diaper rash ointment, and even potatoes. The user originally set out to test different types of thermal pads but decided to expand into other substances, making for an interesting and entertaining study in GPU cooling with some substances that are definitely not safe for long-term use.

The test system used a Radeon R7 240 with a 30W TDP, with temperature readings from a five-minute run of Furmark. As such, these tests aren't a great indicator of the long-term feasibility of using a potato to cool your chip, so here's a statement of the obvious: Don't try this at home.

The user shared a spreadsheet showing the findings, including 22 different tested thermal "paste" materials. The list includes several standard thermal pads of different sizes, including Arctic TP2 0.5mm, 1mm, 1.5mm, Arctic TP3 1mm, 1.5mm, EC360 Blue 0.5mm, EC360 Gold 1mm, 0.5mm EKWB, and Thermal Grizzly Minus 8 thermal pads.

With those relatively safe choices out of the way, next up is the unusual substances not designed for thermal conductivity in a GPU application, including double-sided aluminum copper tape, cheese slices, potato slices, ketchup, copper paste, and Penaten Creme for diaper rashes. The enthusiast also used a broad range of toothpastes, including a few brands you might not recognize, like Amasan T12, Silber Wl.paste, Kupferpaste, and a no-named toothpaste with no branding. 

Naturally, most of the worst performers ended up being almost all of the food-related items.

Several items caused the GPU to engage its thermal throttling mechanism due to overheating as the GPU hit its maximum temperature of 105C, including the sliced cheese and potato slices. Some thermal pads also didn't fare well, with throttling occurring with the EC360 Blue 0.5mm thermal pad, 0.5mm EKWB pad, Arctic TP2 1mm pad, Arctic TP2 1.5mm pad, Thermal Grizzly Minus 8 1.5mm pad copper tape. The double-sided aluminum adhesive pad was the worst offender of them all — it caused the system to shut down. The Pentaten Creme (for diaper rashes) and copper paste were also problematic.

However, the rest of the thermal applications were functional and did not cause the GPU to thermal throttle. This includes the 0.5mm Arctic TP2 thermal pad, 1mm Alphacool Apex thermal pad, Arctic TP3 1mm thermal pad, 1mm EC360 Gold thermal pad, and 1.5mm Arctic TP3 thermal pad. All of these thermal pads kept the GPU anywhere between 61C and 79C.

The various different kinds of toothpaste did decently well, too, with the Amasan T12 coming out on top at 63C, Silber Wl.paste at 65C, and the plain no-named toothpaste being the worst, hitting 90C. Surprisingly, the Ketchup did exceptionally well, keeping the GPU at 71C.

There were two contestants for the regular thermal paste — Arctic's MX-4 and Corsair TM30. Unsurprisingly both kept the R7 250 at the coolest temperatures out of the bunch, with a temperature result of 49C and 54C, respectively.

We don't recommend using anything besides proper thermal interface material on your GPU, but these findings are quite interesting, even if they are as impractical as it gets.

If you're looking for a broader selection of thermal paste testing, we also have a broad selection of testing with CPUs, including toothpaste, in our Best Thermal Paste for CPUs 2023: 90 Pastes Tested and Ranked article. 

Arctic has officially launched its MX-6 Thermal Paste series with immediate availability direct and via Amazon. The successor to the popular MX-5, Arctic reveals that the new substance is “based on the proven MX-4” formula. The key boast for MX-6 is that it “achieves up to 20% better performance” and increased viscosity.

We first heard that Arctic was brewing up MX-6 thermal paste in September, in the wake of Arctic MX-5 being moved to end-of-life, as the firm’s website flagged. The MX-5 had a short run at the top of Arctic’s thermal paste product stack. It was only launched in 2021 and coexisted with MX-4 throughout its lifetime.

So, how does the new Arctic MX-6 compare to its predecessors? For a thorough technical comparison, please study the table above. The most glaring change is in viscosity, with the new paste said to be “especially suitable for direct-die applications.” It is thus also resistant to leakage between the processor and cooler due to the ‘pump-out effect.’ Despite the seemingly astronomical viscosity figure, the new paste claims to be very easy to apply, and it looks pretty ordinary in the application demo video seen below. Another comment we have about the specs is that the popular conductivity metric (W/mk) used in thermal compound comparisons is unknown.

Applying thermal paste method video updated for Arctic MX-6

In our massive best thermal pastes roundup this year (with 90+ pastes tested), we noted that Arctic MX-5 had a thermal conductivity of 6.0 W/mk, a little lower than MX-4’s 8.5 W/mk. While we don’t have figures yet, Arctic says that MX-6 is 20% better than MX-5 (we assume, as it is replacing MX-5). Other performance claims for the new Arctic MX-6 include mixing first-class performance with a fair price. It does so by eschewing rare ingredients such as diamond dust or precious metal particles, and there is no mention of nano-particle science.

Regarding materials, Arctic says that MX-6 is carbon filler-based and features a silicone gel as a carrier for optimal distribution and even contact pressure. MX-6 remains a non-conductive paste, and it isn’t capacitive either, eliminating the risk of short circuits or discharges caused by messy applications or accidents. Arctic says an application should be good for up to eight years with this new formula.

Our previous article mentioned some early (Euro) pricing for Arctic MX-6, which was a bit alarming. Thankfully, the official pricing is far more palatable. MX-6 pricing starts at $12.99 for 2g, going up to $18.99 for 8g. So you can get this for as low as $2.38 per gram, which is better than MX-5, and quite competitive. However, don’t run out and buy any new untested and unproven thermal paste – which you will rely on for up to 8 years – before digesting some third-party reviews. Hopefully, we will have some independent insight into the new Arctic MX-6 soon and be able to determine if it is one of the best thermal pastes.

The cooling experts at Noctua have announced a new product designed to prevent accumulations of thermal paste in the nooks and crannies of AMD’s latest Ryzen 7000 series ‘Raphael’ processors. Noctua’s NA-TPG1 works simply enough, functioning as a barrier, hugging the contours of the AM5 processor with its precisely cut from polycarbonate form. It is designed as a physical barrier to any errant thermal paste which may emerge when a CPU cooler is installed.

AMD’s latest AM5 socket processors certainly are easy to distinguish with their eight thick legs, but PC enthusiasts and DIYers are worried about thermal paste squeezing out and getting stuck in the crevices when a cooler is strapped on. We know of no particular issues a little bit of non-conductive thermal paste might cause other than it looking somewhat unsightly. Nevertheless, a tidy and clean PC build is always preferred.

The Noctua NA-TPG1 is made of “highly heat-resistant polycarbonate,” according to the cooling accessory maker. In addition, its “tight seal” around the irregularly shaped Ryzen 7000 heatspreader should ensure no leakage.

As users may swap and repaste their CPUs and coolers from time to time, Noctua’s standard NA-TPG1 offering comes with a ten-pack of NA-CW1 cleaning wipes. In addition, there are two different SKUs; one with a bundled tube of NT-H1 thermal paste and another with a tube of NT-H2 thermal paste. If in doubt, Noctua published a guide to applying thermal paste to one of AMD’s new Ryzen 7000 CPUs in late August.

Noctua says the above-mentioned product combos will become available in December. This is pretty quick for the Austrian firm, which is well known for delaying products on its roadmap for years. The SKUs and pricing are listed below:

• NA-TPG1 thermal paste guard: EUR/USD 7.90
• NA-TPG1 with NT-H1 3.5g AM5 Edition: EUR/USD 9.90
• NA-TPG1 with NT-H2 3.5g AM5 Edition: EUR/USD 13.90

For further information about thermal paste choice, and our evaluation of Noctua formulations, please check out our Best Thermal Paste for CPUs 2022 guide, which considers more than 90 brands/formulations.

Igor’s DIY solution

The worry of thermal paste getting where it shouldn’t on AM5 platforms was enough for Tom’s Hardware Germany alumni Igor Wallossek to write a page about preventing the issue in a DIY manner. If you follow the link you will read and see photos of Wallossek’s painstaking process of cutting and applying electrical insulation tape – for the same result of using a NA-TPG1, but instead using some materials you might already have at home.

Update 09/22/2022 3:00 pm PT

Amazon Germany has listed the Arctic MX-6 for a whopping price of €28.75 ($23.76 without VAT) per 4 grams.

Original Article

Arctic's MX-series thermal compounds are among the most popular, among PC builders, and the company's MX-5 is widely considered the best thermal grease that it produces. But earlier this week MX-5 status was changed to end-of-life at the company's website (as discovered by @momomo_us) as apparently it is readying all-new MX-6 thermal paste.  

The biggest surprise is that Arctic discontinues its MX-5 just about 1.5 years after its launch in early 2021 and weeks before AMD and Intel are set to start selling their Ryzen 7000-series 'Raphael' and 13th Generation Core 'Raptor Lake' processors with increased maximum processor power. Yet, two images of the Arctic MX-6 packages posted by @momomo_us, a high-tech leaker with a good reputation, indicate that the new thermal grease is incoming. 

Arctic's MX-5 thermal grease is comprised of aluminum oxide, aluminum powder, aluminum nitride, polydimethylsiloxane, magnesium oxide and boron nitride. The paste consists microparticles which fill cavities on the surface of CPU heat spreaders as well as cooler bases. Thermal conductivity of the MX-5 is 8.5 W/m-K and it has a temperature range between -40 and 180 degrees Celsius, which essentially means that it's not designed for extreme overclocking. It has a viscosity of 550 pascal seconds, which is below that of MX-4, but it is still easy to apply. 

Arctic introduced its MX-5 in 2021, but its thermal conductivity did not change from MX-4 launched in 2019. While 8.5 W/m-K is not bad compared to cheap and mainstream thermal greases, it is considerably below thermal conductivity of market leaders like Thermal Grizzly's Kryonaut and Kryonaut Extreme that are designed with extreme overclockers in mind. In general, the MX-5 shoed very good performance under normal conditions, according to our rating of the best thermal pastes for CPUs around, but it looks like Arctic has something better, which is why it replaces the MX-5 while keeping the MX-4 afloat. 

Arctic's MX-5 did not replace the MX-4 and the two pastes continued to co-exist up until recently, even though the new one often performed better than its predecessor. By contrast, the MX-6 actually replaces the MX-5. 

We don't yet know exactly what to expect from  MX-6, but our hunch tell us that this will be a yet another all-around performer from Arctic, but perhaps designed to better suit the upcoming CPUs from AMD and Intel. In any case, the new thermal grease should be available shortly, so we are going to find out soon enough.

Cooler Master is promoting its new CryoFuze Violet high performance thermal paste. One of the interesting aspects of the product is that it moves thermal pastes away from gray gloops into the more glamorous world of violet amalgams. Not coincidentally, the thermal compound’s color is something like Cooler Master's signature shade.

Beyond the headlining color, which hardcore PC enthusiasts and DIYers aren’t going to care about (much), Cooler Master claims some decent technical specifications for its purply paste. Its thermal conductivity value is 12.6 W/mK, which is at the higher-end for pastes that aren’t electrically conductive. Interestingly, Cooler Master CryoFuze Nano has a slightly higher 14 W/mK rating.

For reference, in our recent roundup of 90 pastes tested and ranked, our favorite from the whole bunch offered 11.2 W/mK. Moreover, industry standard bearers like Arctic MX-5 offers 6.0 W/mK — not all conductivity is rated equally, in other words.

Of course there are a multitude of other properties that differentiate pastes good and bad. Other qualities of the CryoFuze Violet include its easy application, thanks to a balanced viscosity. Cooler Master also says the paste is exceptionally stable at a wide range of temperatures (-50 to +240 degrees Celcius). It claims that it won’t dry out, and that it is non corrosive.

CryoFuze Violet uses nanoparticles to increase thermal conductivity, but it is by no means pioneering this material technology. Our two favorite pastes, ProlimaTech PK-3 Nano Aluminum and Thermal Grizzly Kryonaut, use this tech, as does the recently released Alphacool Apex.

Cooler Master provided an instructional video, making clear once and for all what it felt was the best way to apply thermal paste, when it launched the first CryoFuze Nano. According to the video you should squirt lots of paste on your CPU before poking it around with a plastic paddle. The process looks a lot like an amateur baker icing a cake. But then last week we saw Igor Wallossek painstakingly measuring and manipulating thermal paste on a GPU, and he found the ‘buttering’ of the chip pasting method to be the worst possible (a simple sausage was best).

As mentioned above, we compiled a Best Thermal Paste for CPUs 2022 list a few weeks ago, checking over 90 alternatives. Until we have had time to scrutinize Cooler Master’s CryoFuze Violet amalgam, it might be wise to stick with something gray.

Cooler Master didn’t mention pricing or availability, but we spotted a CryoFuze Violet 2g twin-pack available via Newegg, priced at $30.99 (ships from Hong Kong). Hopefully when it reaches local distributors it will be more affordable.

The correct way to apply the best thermal paste has been a hotly-contested topic among PC enthusiasts since PC DIYing began. Some people swear that the best application method is in a central blob, a cross, a line, more complex patterns, or even spread on the chip like butter on a cracker. Igor Wallossek of Igor’s Lab sought to test and demonstrate the best method of thermal paste application for GPUs, not CPUs. Igor found that the best method resulted in a liquid-cooled GPU which ran five degrees Celsius cooler than the least favorable method.

In what is, in essence, Igor’s GPU re-pasting guide, he starts by talking about how important correct thermal paste application is on large GPUs. Smaller GPUs are more forgiving, but larger, more powerful ones have uneven surfaces and may suffer from warping when under the tension of the cooling assembly. We have seen similar tales of warping recently with the elongated Alder Lake CPUs, which are thermally improved by the use of mounting frames.

Igor also stresses the importance of cleaning off the old thermal paste properly. He provides a walkthrough of his methods, what to look out for, and what to not fuss about.

Interestingly Igor asserts that due to the ‘brutal’ gaps between a GPU and a cooler, using a high-viscosity thermal paste is essential. For GPUs, he emphatically dismisses popular products like Arctic MX-2 or MX-4 but puts a good word in for Alphacool Apex or Subzero or “the old Gelid PC Extreme.”

Before applying the paste to the GPU, you should try and get it to a ‘hand-warm’ temperature, and the same applies to the GPU. Igor suggests putting the thermal paste tube in a pocket for a few minutes and checking the GPU die isn’t ice cold. Before and after application, a bit of hair dryer action might help keep the viscous paste easily workable.

On the controversial topic of thermal paste application shapes, Igor tested a GPU that was fully ‘painted’ with paste vs a central blob vs a vertical line (the titular sausage). Sadly he missed out on the central cross and several other popular methodologies/permutations. For example, look at Noctua’s CPU pasting recommendations which came to light earlier in the week.

Sausage Wins, but Relies on a Seesaw Screw Tensioning Method

The sausage-style central vertical line was the easy winner in Igor’s tests. However, its use is wedded to a particular method of screw tensioning. First, when re-attaching the cooling assembly, you must place it straight down onto the GPU without sliding around. Then you must apply a little tension to one side pairing of screws, followed by the other side, then back and forth a few times – working it like a seesaw.

In his tests, the sausage method was quite an obvious winner, offering about a five degrees Celsius improvement over other methods. Igor says he used liquid cooing for consistent results with his GeForce RTX 3080 reference PCB.

Wrapping up, Igor stands solidly by his pasting and cooler tensioning method, saying some manufacturers follow a very similar method to that outlined above. Perhaps readers can try this methodology next time they re-paste an old GPU. Let us know what you think in the comments below.

There are so many thermal pastes to choose from in 2022. If you are confused by the choice, it is worth having a look at our best thermal pastes roundup, considering 90 products.

A team of researchers from the Massachusetts Institute of Technology (MIT), the University of Houston, and others may have just stolen a glance at the future of computing. And according to their report, published in Science, it looks much less silicon-based than we might think. Scuttle over, silicon. Cubic boron arsenide is here with lower temperatures,  better electrical conductivity, and improved performance that could thus soar alongside compute density.

However, as these things usually go, we're likely talking decades of research before an actual product - let alone a new age of semiconductor manufacturing - can be brought to etch. Silicon's dominion on almost all things compute - from the processor inside your calculator through the world's most powerful supercomputer - is too entrenched in decades of expert problem-solving to be dislodged that fast. The same isn't true of boron arsenide, which still has to prove its operational longevity.

The issue with silicon is that it's a compromise. It is a laughably bad thermal conductor - which is part of the reason why our electronics heat so much that one could cook an egg on a CPU if we so chose. Silicon also only really has a good handle on the negatively-charged electrons - whose ordered movement, as you might have learned in school, is what electrical current is made of. "Holes" - electrons' positively charged inversions - don't gel so well with silicon. Despite these hiccups, silicon is abundant and relatively easy to manufacture.

Cubic boron arsenide (c-BAs) - made out of boron and arsenic - fixes both of silicon's problems. It's equally accommodating of electrons and holes, leading MIT professor of mechanical engineering Gang Chen to call it "really unique" in the world of semiconductors. “That’s important because of course in semiconductors we have both positive and negative charges equivalently. So, if you build a device, you want to have a material where both electrons and holes travel with less resistance,” Chen said.

It also conducts thermal distress up to 10x better. This means heat dissipates much faster from its surface - much faster, actually, than it does even in copper, the element of choice for your aftermarket cooling solutions. While silicon has a typical 148 W/mK thermal conductivity, copper improves that by a factor of three, at 401 W/mK. The researchers' cubic boron arsenide, on the other hand, can dissipate heat around the 1200 W/mK mark. It's like comparing the Little League against its bigger, badder, more competitive MLB brother.

“This is impressive, because I actually don’t know of any other material, other than graphene, that has all these properties,” Chen added. “And this is a bulk material that has these properties.”

“Heat is now a major bottleneck for many electronics,” said MIT postdoc Jungwoo Shin Shin, the paper’s lead author. “Silicon carbide is replacing silicon for power electronics in major EV industries including Tesla, since it has three times higher thermal conductivity than silicon despite its lower electrical mobilities. Imagine what boron arsenides can achieve, with 10 times higher thermal conductivity and much higher mobility than silicon. It can be a gamechanger.”

By all current accounts, boron arsenide is the ideal semiconductor. The issue with boron arsenide is that it's exceedingly more difficult to produce than silicon. So far, only lab-scale production runs of the compound have been made. The batches aren't uniform, either - further muddying up the waters for an eventual adoption as a mass-transformable semiconductor. The researchers currently aren't sure whether it can be harnessed in a practical and economical form. Likely, it wouldn't be as ubiquitous as silicon in the computing world. Still, it could be used for critical, particularly heat-producing components or even as a heat transfer medium embedded into silicon designs.

 “Silicon is the workhorse of the entire industry,” says Chen. “So, OK, we’ve got a material that’s better, but is it actually going to offset the industry? We don’t know.”

So perhaps silicon doesn't need to break a sweat anytime soon (although, being a poor conductor as it is, it probably will anyway). But even as power efficiency and compute density hit materials bottlenecks - especially as we enter the Angstrom era of computing - maybe it does need to worry about sharing the world's stage.

PC components stalwarts NZXT and Alphacool have launched new thermal pastes. NZXT's new paste — its first-ever thermal paste — is dull-but-descriptively named NZXT High-performance Thermal Paste ($9.99/3g, $19.99/15g). Alphacool claims its new thermal paste, called Alphacool Apex Thermal Paste (€14.99/4g), is the best non-liquid metal thermal paste. Both thermal pastes are electrically non-conductive and are touted as easy to apply, with long-term stability.

The thermal compound that you put between your CPU and cooler (or in re-pasting your GPU, or laptop) can make a significant difference to cooling performance, so it's worth considering carefully when you build or maintain a PC. We tested over 90 different pastes (thermal and non — we even tested toothpaste) in our exhaustive round-up of the best thermal pastes, published earlier today. However, NZXT and Alphacool's new products have somewhat spoiled the comprehensiveness of our coverage — we'll have to test them once we get our hands on them.

Over recent years there have been some esoteric pastes made with materials such as diamond and liquid metal (which can be hazardous due to electrical conductivity and chemical reactions with aluminum). These new pastes from NZXT and Alphacool are more traditional: non-electrically conductive, non-corrosive, and easy to apply and clean off.

For a better handle on the new thermal pastes and how they compare, take a look at the specs.

The new Alphacool Apex thermal paste has a much higher claimed thermal conductivity value, and its marketing material asserts it is "one of the best performing thermal pastes on the market," which is only beaten by liquid metal alternatives. Meanwhile, the slightly cheaper (much cheaper if you buy it in bulk) NZXT High-performance Thermal Paste has thermal conductivity on a par with PC-builder-favorite Arctic MX-5 — so its performance is by no means poor.

NZXT says its paste uses zinc oxide, liquid polymer, and aluminum material. Alphacool isn't as forthcoming with its ingredients, and instead says that its thermal paste is formulated using "a nano-powder with a very low thermal impedance." So, it looks like Alphacool's new paste relies on nanotechnology-boosted thermal conductance.

If you're not sold on NZXT's first foray into the market or Alphacool's nanotech-infused secret sauce, we suggest going for one of the picks in our best thermal pastes round-up (not toothpaste).

Streacom is attempting to answer the age-old question: "How much thermal paste should I use?" It's doing so by providing PC builders a serving size of one packet per application to a heat spreader with packaging designed to reduce plastic waste.

In a news release, Streacom announced that it had partnered up with Eden Reforestation Projects, a non-profit organization known for fighting deforestation in Central America in order to change its packaging to reduce its environmental impact. 

In each package of Streacom's TX13 thermal paste, you are given five packets, ensuring that you will have enough paste for exactly five standard desktop CPUs, (but you may need more than one for a Threadripper or LGA 3647, which have larger IHS'). The packaging consists of a recycled cardboard envelope and doesn't include a plastic spreader.

You are provided with enough paste per packet to make a "pea-sized" dot, the TX13 thermal paste features a thermal conductivity of 13.4W/m-k, which may make it a contender for our list of options the best thermal paste. Streacom also claims that this amount of paste, .25 grams, is enough to make an "X" pattern on the IHS, too.

For each pack purchased, Streacom is sponsoring the Eden Reforestation Project to plant a tree.

Streacom has yet to announce a price, but with its high level of conductivity and the feeling of doing something good for nature, the TX13 thermal paste may be worth keeping an eye out for.

Arctic's MX-4 thermal compound has proven itself well in the DIY space, but it's been around for quite some time and seemingly, like everything in tech, in need of an update. So in comes, low-and-behold, the MX-5. The MX-5 thermal paste hasn't been officially announced yet nor is it listed on Arctic's website, but hardware detective @momomo_us found the compound listed on Amazon UK paired with an informative description.

Although full specifications aren't available at this time, what stands out most about the description is the paste's durability: it's alleged to last for up to eight years once applied.

Of course, enthusiasts generally change CPU multiple times in eight years, but MX-5's alleged durability can be extremely helpful for use in laptops, GPUs, or that PC you're building for a relative. Its not clear what the MX-5's thermal conductivity is, but if Arctic's historic products are anything to go by, it should be pretty good. 

MX-5 is metal-free and non-conductive, so it's also safe for use on GPUs without needing to worry about over-spilling on the area around the GPU.

A single 4g tube of paste (enough for well over a dozen builds) is listed on Amazon UK's site for £13.59, which translates to about $18.50. That's probably pre-order pricing though, and it will likely drop in due time. According to Amazon the MX-5 thermal grease will be released on March 15 2021.

Thermaltake have launched the TG-30 and TG-50 thermal compounds that come with an interesting way of applying them to the processor's IHS (integrated heat spreader). The biggest novelty with the TG-30 and TG-50 is that Thermaltake includes a honeycomb-patterned stencil and a small spatula to paint the thermal compound over the IHS. The stencil is compatible with both Intel and AMD processors.

The company didn't reveal the thermal compounds' composition and the product page only hints to the presence of some mysterious diamond powder that reportedly helps with thermal conductivity. Thermaltake claims that the TG-30 and TG-50 don't dry up or crack easily either.

The rationale behind Thermaltake's idea is that the CPU cooler exerts uniform pressure over the honeycomb droplets so they spread and cover the entire IHS on the processor. Think of it as a simpler version of the credit card method. The only caveat we see with Thermaltake's approach is that you waste a good amount of thermal compound in the application process.

Thermaltake sells the TG-30 and TG-50 in 4g syringes. In addition to the stencil and spatula, the brand also includes two alcohol rubs to remove existing thermal compound from your processor or for cleaning the stencil after use.

The TG-30 boasts a thermal conductivity of 4.5 W/m-k, while the TG-50 delivers up to 8 W/m-k. Thermaltake sells the TG-30 and TG-50 for $8.99 and $11.99, respectively.

From IFA tech show in Berlin, Acer shared some of the latest innovations and products, including new laptops, a second-gen Thronos gaming chair, and the new Predator PowerGem. The PowerGem is a new thermal pad developed to cool CPUs. The company claims the new product will conduct heat nearly four times faster than copper and can improve CPU performance up to 12.5%. 

The result of this more efficient TIM Acer claims, yields over a 77.7% increase in power envelope handling yielding that 12.5% CPU performance bump. The product will still need a heatsink on top for a laptop, while the desktop still requires a heatsink and fan for its higher wattage. 

When talking to the representative, we asked for some context on the testing, but few details would be provided outside of the numbers being based on a typical laptop cooling solution using a copper vapor chamber. He also shared a belief that the TIM was better than liquid metal, but still needs more testing to confirm. We'd love to get a sample in house to see exactly how it fares against other more common TIMs. 

Outside of the increased heat conductivity, it is expected this could reduce the size of heatsinks/vapor chambers inside of laptops allowing for higher performing and potentially thinner and lighter devices. Acer plans to use the PowerGem in the new versions of its Helios 700 series laptops and Orion 9000 desktops. Jason Chen (CEO of Acer) also mentioned it can appear in the ConceptD lineup as well. 

If this new TIM/pad is all it's cracked up to be, the next question is will they sell the material to directly to users in the DIY market. Unfortunately, that point was not made clear. For now, we'll have to see these in the laptops and other future devices from Acer only. 

Cooler Master is revamping its MasterGel series of high-performance thermal paste with a new line featuring a slogan that asks "Why copy paste... when you can swipe?" That's right, the new thermal paste is meant to be swiped -- or spread -- across your CPU's IHS.  

There are many methods to apply thermal paste to a CPU. If you're not good at spreading thermal paste evenly, Cooler Master's renewed MasterGel can do the work for you. The syringe features a flat-nozzle head that allows you to spread the thermal paste almost effortlessly. Say goodbye to spreading thermal paste with a credit card or smudging it with your finger. Cooler Master's implementation is so simple that we're surprised no other brand has thought of it before. 

Cooler Master's announcement today didn't fully detail whether the new MasterGel thermal paste is produced any differently from its predecessor. The previous MasterGel thermal paste is made from nanodiamond particles. It isn't electrically conductive and doesn't require any curing time. The product pages do say that the new thermal pastes use "nanoscale" technology for "high conductivity and high anti-erosion" and can also be used with graphics cards. 

The latest MasterGel thermal paste is available in three different tiers. The MasterGel Maker boasts a thermal conductivity of 11 W/mK, while the MasterGel Pro and MasterGel Regular are certified for 8 W/mK and 5 W/mK, respectively. Cooler Master lists the MasterGel with a specific gravity (just a fancy way to refer to density) of 2.6 g/cm³. 

Regardless of the model, the MasterGel thermal paste comes inside a small 1.5ml syringe. It also comes with a cleaning cloth so that you can clean old thermal paste off or any thermal paste left over after applying the MasterGel.

Cooler Master didn't reveal the pricing or availability for the MasterGel Masker, Pro and Regular thermal paste.

Disassembly, Modification & Test System

As we mentioned in AMD Ryzen 5 2400G Review: Zen, Meet Vega and AMD Raven Ridge Thermal/Power Analysis: Ryzen CPUs With Vega, the company is using thermal paste instead of solder between its newest dies and heat spreaders. Measurements in the latter story showed that neither Raven Ridge-based model hit its thermal limit using AMD's boxed cooler, even under Prime95. It was only when we pushed the execution cores and graphics engine at the same time that we overwhelmed its stock heat sink and fan.

Of course, this doesn't stop enthusiasts from asking what might have been if AMD had used solder instead, or from speculating about the quality of its thermal paste. And the only way we're going to get answers to either of those questions is removing a Ryzen processor's heat spreader and running some experiments. 

A Clean Cut: Heat Spreader Removal

Whether you use a de-lidding tool or a good old fashioned razor blade is up to you. But because AMD employs a silicone-like adhesive layer ~0.2mm thick, the razor blade is a reasonably-priced option. Begin your cut exactly where AMD left a gap in its adhesive.

The only real challenge is getting around the surface-mount components placed close to the adhesive layer. Try positioning the processor vertically and cutting from top to bottom, leading the blade at a slightly slanted angle. Use multiple movements, starting from the outside and cutting in. If you feel resistance, stop immediately, then pull the blade slightly upwards and out.

Next, the old thermal paste needs to be removed from the opened processor. We recommend using a thin, dry fleece cloth, rather than a fuzzy kitchen or paper towel. It is best to wipe around the die in a circle, starting from the outside and moving inwards. You may use a bit of isopropyl alcohol or, if necessary, methylated spirits for cleaning up. However, acetone-based solutions are taboo.

Use the blade (a new one, preferably) to remove any remnants of the silicone glue. This is necessary to ensure that the heat spreader has an even surface to mate with once it's reinstalled, and to avoid too large of a gap.

Intermediate Step: Conventional Thermal Paste

If you go to the trouble of removing the heat spreader, it's highly unlikely that you'd simply swap one thermal paste for another. But rather than going straight to liquid metal, we want to know how AMD's proprietary solution compares to off-the-shelf Thermal Grizzly Kryonaut (one of the best non-conductive, silicone-based thermal pastes available).

So, we're adding one extra step, if only to satisfy our curiosity about AMD's thermal paste and hopefully gain a little more knowledge.

Applying Liquid Metal Paste

For the third and final set of data, we used Thermal Grizzly Conductonaut. This liquid metal "paste" is relatively easy to apply, so long as the die and heat spreader surfaces are absolutely free of grease and dust. Otherwise, the paste won't hold, yielding an unsatisfactory result.

In addition, you need a good, acetone-free clear coat. Try a transparent nail polish without any color or effect pigments. Make sure to shake it well prior to application. To avoid breaking the processor's delicate pins, it helps to rest the chip on a suitable foam surface.

Judiciously cover the surface-mount components and the empty emplacements with your application of polish. Multiple applications may loosen or remove the package's original lacquering, and should thus be avoided. After that, the polish has to be left alone so that it can cure. For the polish to dry properly, wait at least one hour in a warm-enough environment.

Next, it's time to apply the Conductonaut. For this, we cover the die and matching elevation in the heat spreader with a very thin layer. It is better to use a little less at first, and then add more later if needed. The bundled applicator (the thin, attachable top) has to be used. Otherwise, too much of the liquid comes out.

The liquid is then spread in a circular motion using the included foam sticks. Make sure the desired surfaces are covered completely in a thin layer, and that none of the liquid spills over the edge. Should this happen when you go to press the pieces together, the polish you applied will help protect against potential short-circuits.

Finally, the heat spreader is reattached and glued in place with either cyanoacrylate or silicone. All-purpose glue isn't sufficient for keeping the head spreader in place, even if its packaging claims the contents are suitable for metal. Keep in mind that the glue must fill a gap of ~0.2mm so the adhesive still safely connects both sides after curing. Glue would be applied to both sides of the heat spreader, while silicone is only applied to the package. Make sure to attach the heat spreader in its correct orientation.

For perfect pressing and drying, carefully put the processor back into the socket, apply a small dot of high-quality thermal paste, and assemble the boxed cooler carefully. Alternately tighten the screws crosswise, and make sure not to tilt or move the heat sink. After a short temperature check with monitoring software like HWiNFO64, being a burn-in process with Prime95 and be ready to keep an eye on its progress. An hour should be more than sufficient to achieve production-ready performance, though silicone needs about a day to cure properly.

Test Setup

In order to establish the limits of AMD's Raven Ridge-based processors, we need to push them as far as they can go. That's where Alphacool's powerful Eiszeit 2000 Chiller comes into play. We combine it with the Alphacool Eisblock XPX, replacing AMD's Wraith Stealth heat sink. Motherboard components are cooled by 22°C air from a large fan blowing across them.

A short summary of our hardware in table form gives you a quick overview of how we test:

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Test Results & Conclusion

Temperature & Power Consumption

Our thermal data yields a couple of surprises. First, the paste that AMD uses between its die and heat spreader performs better than we believe a lot of enthusiasts were expecting. Second, it'd be hard for anyone to improve on the stock configuration, since the paste is applied so thinly to the heat spreader during production.

Gluing the heat spreader under pressure furthermore ensures an optimal result. When we carefully removed the original layer of thermal paste, we took note of how much AMD used and replicated its effort with our own high-quality stuff. Upon removing the heat spreader a second time, we confirmed that our application looked just about as perfect as AMD's.

Nevertheless, we did not succeed in achieving a noticeable advantage over the original paste's performance. Not even a burn-in over several hours helped to significantly improve our findings. The hotter Ryzen 5 2400G became, the smaller the already tiny difference got. In addition, when we used the boxed cooler, both applications of thermal paste failed to keep AMD's chip from hitting its thermal limit with Prime95 and MSI Kombustor running. Naturally, then, replacing the stock paste with another silicone-based paste is pointless. AMD makes the best of its position by achieving optimal performance within the framework of industrial mass production and pressure to cut costs.

Our modification using liquid metal is another story entirely: it's the best solution, no doubt about it. The temperature differences range from ~9-11°C during gaming. Though, to be honest, the effort required is a little excessive given our results. It's not like thermals were a big issue to begin with, even under overclocked settings. Temperatures are only a limiting factor with stress tests running, and in those cases, the liquid metal does help by up to 17°C.

Liquid metal only makes sense if you're operating within the absolute upper range of this processor's limits. Otherwise it's merely nice to have.

The boxed cooler hardly gets any quieter, either. A rather humble drop of just 135 RPM (at best) during normal operation doesn't significantly reduce the background noise we described in our launch article. Under full load, this benefit shrinks to a 40-50 RPM improvement, which is hardly distinguishable at all.

The conversion would definitely be worthwhile if you replaced the cooler with a quieter version and installed the chip in a small form factor chassis without good airflow. Then, the temperature delta could be the difference between what works and what doesn't. But for everyone else, the time and money won't net an appreciably better outcome.

We can't really fault AMD here. After all, the competition uses thermal interface material on its highest-end CPUs aimed at enthusiasts. At least for that market, AMD still applies solder.

Power consumption comparisons between the two thermal pastes are pretty much identical; measured differences land within a margin of error.

Power consumption doesn't drop unless the temperatures fall significantly first. Even then, a maximum of 3W in an extreme case is not exactly earth-shattering. Perhaps if our sample hadn't throttled, the values would be a bit higher. It is also worth mentioning that, apart from the stress tests, CPU and GPU frequencies change very little. In no case is it possible to achieve a significantly higher clock rate by following our footsteps. Even during our stress test, Ryzen 5 2400G doesn't achieve an average gain of more than 75 MHz with liquid metal.

Summary & Conclusion

Yes, replacing AMD's paste with liquid metal works well, facilitating improved thermal performance compared to a stock Ryzen 5 2400G. It's just too bad that you won't see much of a practical difference. There's not much added value, and AMD's processor is neither faster nor more power-friendly in the end.

The only measurable benefit is lower temperatures. Unfortunately the boxed cooler is not really able to take full advantage of lower temps without changes to its fan profile. Hours of work, notable risks, and minimal benefits just don't balance out. Thus, this modification is only worth considering if you're building a seriously compact PC.

Our findings may give you reason to complain about AMD's cost-cutting or praise the company for its execution. At a financial level, AMD made a reasonable decision. But when it comes to enthusiast mind share, shifting over to thermal paste is bound to raise eyebrows. On the other hand, are gamers buying eSports-ready PCs likely to argue about what's between their dies and heat spreaders?

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Take Off Your Top! Radeon R9 290X Gets Naked

In Radeon R9 290X Review: AMD's Back In Ultra-High-End Gaming, we pointed out that the company's reference cooling solution, coupled with the launch drivers, had consistency issues when we looked at GPU clock rates. An enormous amount of feedback poured in, and we followed up with The Cause Of And Fix For Radeon R9 290X And 290 Inconsistency, which identified inaccurate PWM fan control as one source of trouble.

Two questions rose to the top during the subsequent discussion in our forum:

1. Is there anything to gain from reattaching the heat sink and maybe replacing its thermal compound?
2. Does improving cooling performance help the card run at a higher efficiency level? Is so, pinning our hopes on the partner boards would be entirely warranted.

We ordered yet another retail Radeon R9 290X branded by Gigabyte after already going through Asus and Sapphire cards. None of these three vendors have any control over build quality; they're all purchased from AMD and slapped with a sticker to identify a board partner. That's why none of those three companies can be held responsible for the issues with the cards we're testing. When we asked Gigabyte about modifications made to AMD's reference, the company said that it doesn't change a single thing or replace any of the parts. And that includes messing with the heat sink or fan. Why is this such a big deal? You're going to see in just a second.

In a continuing effort to answer questions, we carefully started to strip down our third retail Radeon HD 290X to expose the bottom of AMD's thermal solution, as well as the graphics card's PCB.

The Hawaii GPU and the heat sink covering by a too-thick layer of thermal grease, resulting in less-than-efficient heat transfer. You might remember our word of caution against this from our thermal paste comparison.

We collected and saved the thermal compound used by AMD from two Radeon R9 290X cards for additional testing. This was enough to cover the surface of a CPU's heat spreader, which makes us doubt that the quantity of paste used on this first round of boards corresponds to what you'd typically expect from mass production. It bolsters our theory that the R9 290X comes from a small batch of hand-assembled boards, and that the application of grease is part of the process.

Removing the paste revealed the heat sink’s scratched and uneven contact surface, which did not exactly match the quality you would expect from a brand new and professionally mounted cooler.

Take a close look at the nicks on the copper base: It does not seem like these are only pressure marks resulting from the regular mounting process.

Meanwhile, we left a sparkling clean GPU waiting for a new coating of thermal compound. Then we went back to our thermal paste comparison and tapped a couple of our favorite finishers. Innovation Cooling's Diamond "24 Carat" compound was beyond reproach. So, in order to verify our temperature measurements, we decided to take second and third test runs with that one.

Gelid’s GC-Extreme performed just as well as IC's Diamond. It also cost us less and spread more easily over the GPU. This also applies to Cooler Master's X1 Extreme Fusion. Due to the fact that both Hawaii-based graphics card shoot for high target temperatures, there's no way to distinguish whether one is superior to the others thermally. But we did observe that power consumption and average performance were roughly the same across all of those aforementioned aftermarket compounds. So the following results were collected using Gelid’s GC-Extreme.

Watching Temperatures Rise

There is a significant difference between using AMD's stock thermal grease and the Gelid GX-Extreme. It took us three minutes, instead of just 60 seconds, to push the Radeon R9 290X to its 94 °C limit. Also, Power Tune operated less restrictively. 

We're going to show the incredible impact this has on the card's power consumption and efficiency by setting the Radeon R9 290X to its Quiet mode firmware setting, rather than the ear-battering Uber BIOS.

Power Consumption: Before And After

Our test system for power consumption measurements is a result of a cooperation with HAMEG (Rohde & Schwarz). It gives us the opportunity to present highly accurate values based on the use of a precise multi-channel oscilloscope with remote control.

We log every relevant channel, and all measurement values and graphs get saved to the scope. Our very nice clamp-on ammeters provide 100 mV/A, so we can easily derive current based on the measured voltages. The actual supply voltage is recorded and multiplied by the current later on.

For what it's worth, power consumption peaks do not always correspond to action happening on your screen, as you can see from the following sample video, which also demonstrates how the Radeon R9 290X's power consumption gradually falls, since the card isn't able to sustain consistent maximum clock rates.

Three Runs With AMD's Stock Thermal Compound

We start by running three successive test loops. The Radeon R9 290X hits its target temperature in the last quarter of the first loop, which is also where we see the highest power consumption (and peak performance).

The GPU temperature remains constant during the second loop, while power consumption falls considerably.

Although performance erodes again at the beginning of the third loop, we get consistent results from then on. Power consumption is reduced by another 10 W, and the peaks and troughs in this chart are clearly less intense.

Three Loops With Gelid's GX-Extreme

By using a higher-quality thermal paste, idle temperatures decrease considerably and we gain a slight increase in performance as power consumption rises by 20 W compared to the previous first loop.

Again, power consumption drops during the second loop as the GPU heats up. As soon as the Radeon R9 290X reaches its target temperature, Power Tune takes action and slams on the brakes, although the difference in average power consumption remains at 20 W.

And for the second time, loop number three yields a more consistent result at a lower performance level. The power consumption gap narrows to 12 W compared to this same run using AMD's stock thermal compound.

What have we seen so far? Well, we know that Power Tune takes action as soon as the GPU reaches its target temperature, but it takes some time after that before power consumption decreases significantly. How well is Power Tune working? A drop in power consumption of 11.5 and nine percent between the original and alternative thermal compounds is accompanied by a commensurate performance drop. And what about efficiency? Does replacing the interface material also yield an improvement there? We'll answer that question shortly. 

Performance And Efficiency

In order to extend the comparison, we added several of Nvidia's GeForce graphics cards with and without reference coolers to the charts, including the GeForce GTX 780, 780 Ti, and Titan. Replacing the original thermal compound on AMD’s Radeon R9 290X results in a remarkable performance gain.

During its first loop, the stock Radeon R9 290X is even with Nvidia's GeForce GTX Titan on its third loop. However, it pulls ahead of Gigabyte's factory-overclocked GeForce GTX 780 with its Windforce cooler once we apply our replacement thermal compound. It even comes close to the reference GeForce GTX 780 Ti...at least on its first loop.

Unfortunately, the R9 290X loses ground during the second loop. Its Hawaii GPU is pushed to its temperature limit and gaming performance decreases significantly. The third loop provides the most consistent results, as the card stabilizes on roughly the same average frame rate observed during the second run.

Translated into percentage terms using Nvidia's GeForce GTX 780 Ti as the 100% baseline, you get the following values:

Now think back to the power consumption measurements. The Radeon R9 290X drew less power during the second and third loop. Does this translate to a gain or loss of energy efficiency?

To our surprise the third loop using higher-quality thermal compound turns out to be the Radeon R9 290X's most efficient operational state. In plain English, that means a slightly lower frame rate is accompanied by considerably lower power consumption. This is contrary to what we've seen from the smaller Radeon R9 290, which is able to outperform Nvidia's reference GeForce GTX 780 Ti at an operating temperature of 83 °C once we replaced its original cooler with Arctic's Accelero Extreme III. If you haven't seen that story yet, check out Fixing The Radeon R9 290 With Arctic's Accelero Xtreme III.

The second loop turns out to be least-efficient. Shortly after the card's temperature limit is reached, Power Tune steps in and reins in consumption.

After replacing its thermal compound, the Radeon R9 290X's energy efficiency is just 10 percent behind the three-percent-faster GeForce GTX 780 Ti Windforce GHz Edition during the third test loop and after its limiter kicks in. Thanks to Gigabyte’s excellent cooling solution, its 780 Ti does not exceed a GPU temperature of 70 °C.

Given proper cooling, AMD does pretty well. The Radeon R9 290X could even turn up ahead of Nvidia's GeForce GTX 780 Ti in a measure of frame rate-per-dollar. For now, though, Nvidia's board partners offering custom cooling and factory overclocking maintain a lead over AMD's flagship. That's the last word until AMD's own partners get enough supply of Hawaii GPUs to release modified versions of the 290X leveraging more effective cooling.

Answering Those Questions With Real Data

Our measurements allow us to provide some clear answers to the initial questions based on power consumption and performance values taken from three successive test loops.

What do you gain from replacing the thermal compound?

So long as you choose a good thermal compound and do the job correctly, replacing AMD's stock stuff can really pay off. The biggest problem with this is that you void the manufacturer's warranty in the process.

Does improving cooling performance help the card run at a higher efficiency level?

The answer is clearly yes, it does. Particularly when you see what the Radeon R9 290X can do during its first run through a benchmark, and then compare that to the third run, you have to wonder how the company can willingly throw away a good chunk of performance by using its reference cooler.

You need a set of small Phillips-head screwdrivers to remove the Radeon R9 290X's cooler, since AMD uses two different screw sizes. Tweezers could prove helpful for removing excess thermal paste from the GPU. And don’t forget to keep a cleaning solution handy to prep the die before applying your improved thermal compound of choice.

We recommend Gelid’s GC-Extreme and Cooler Master’s X1 Extreme Fusion. Both are easy to apply and not electrically conductive. If you're brave enough to tackle this mod on your own, bearing in mind the possible consequences, we wish you success and fun. The operation certainly pays off.

39 Thermal Compounds Get Benchmarked And Tested

If you missed part one of this series, take a quick second and check out Thermal Paste Comparison, Part One: Applying Grease And More.

We Are Curious About Two Special Compound Categories

After discussing the theory of conventional thermal pastes in part one, I want to go into a little more detail about liquid metal compounds, and also shed some light on thermal adhesives, both in paste and pad form. Thermal pads are used to mount small heat sinks on RAM chips or MOSFETs.

But let’s start with those liquid metal pastes. While their theoretical thermal conductivity sounds impressive, that one attribute is no guarantee of success. During the course of our testing, we'll be experimenting with a long burn-in phase and comparing the liquid metal compound to Gelid's Extreme paste.

Several years ago, Coollaboratory broke new ground in thermal management by introducing the Liquid Pro liquid metal compound. But while the look (and subsequent application) of Liquid Pro reminded us of a mercury thermometer that didn’t survive a fall, its successor, Liquid Ultra, is better, avoiding some of the first effort's weaknesses. Because Liquid Pro could be so problematic, I'm only presenting Liquid Ultra in the tutorial section. Both compounds show up in our performance charts, though.

Box Contents

In the Liquid Ultra box you get the paste itself, a cleaning swab, two brushes, a sponge, and an instruction manual. That's an impressive-sounding list, but it's really just the bare minimum to use the product, sufficient for a single application. If you want to apply Liquid Ultra a second time, you'll find yourself without the alcohol swab. At least a second brush is included. While we appreciate the inclusion of the coarse sponge, it's barely adequate for removing the compound. Of course, there's a separate cleaning kit available for a hefty price.

Enthusiasts may be torn about this product, and yes, there may even be those who are more courageous than I and use it on graphics cards. However, my personal opinion is that a majority of the people who read this tutorial are new to thermal compounds, and I wouldn’t want to encourage them to mess around with this stuff due to the skill it requires. I also want to point out that you'll probably void your CPU's warranty if you do use Liquid Ultra. After removing the last remnants of it, we discovered that all of the markings etched into the head spreader were gone. If you still want to try this product after reading our tutorial, you can probably expect very good cooling performance, assuming nothing goes wrong.

Surface Cleaning and Roughing

The most important prerequisites for using a liquid metal compound are clean heat sink and spreader surfaces. You can buy the aforementioned kit with the three cleaning liquids, or simply snag some isopropyl alcohol at the drug store. However, stay away from acetone and cleaning naphtha. Even denatured alcohol may contain additives that are detrimental to achieving a clean, degreased surface. Finally, make sure you wait until any remnants of the liquid have evaporated!

If the surface is too smooth, the older Liquid Pro and newer Liquid Ultra may only form loose droplets on your CPU. Thus, in contrast to what you would do for regular thermal pastes, you may consider roughing the heat sink and spreader a little bit. Just remember that you only get enough liquid metal for two tries.

Don't overdo this. If you scrub too hard, the innocent-looking sponge can cause deep grooves. Move in small, graceful circles.

Coollaboratory Liquid Ultra: Application

Applying the compound is tricky, which is why we don't really recommend Liquid Pro. Liquid Ultra is a little more like the pastes you're used to, though still a lot "wetter". Its composition is still a point of concern because it corrodes light metals like aluminum and certain alloys. This could have an adverse effect on thermal conductivity, even causing an insulating layer to form. Copper- and nickel-plated surfaces are alright though, as are heat spreaders.

Once you've roughened up your CPU, you can drip Liquid Ultra on it, spreading it around with an enclosed brush. The amount you'll use varies by CPU size, but plan to use about half of the compound on AMD processors and about a third on Intel's. The video shows that you can even add liquid metal while spreading it out. Depending on the mounting pressure of your cooler, you may want to spread the compound more than the video shows. Just be careful; you don't want this corrosive, conductive material to get squeezed out the sides.

The next video illustrates an alternate method that requires less material. What we want to stress, however, is that it is better to put the liquid metal on a CPU away from its processor interface, thus protecting the motherboard from spills. We're putting the chip on our cleaning sponge to make sure none of its pins get bent.

On one hand, the liquid is spread more evenly and less of it is needed. But on the other, more metal balls form. Since they could cause a short circuit, they need to be collected. This method only works when the surface has been roughened, and it yields (marginally) better results.

Coollaboratory Liquid Ultra: Application Problems And Clean-Up

The pictures below are staged. But their purpose is to warn you what might happen if you're not careful, or if you don't pull the CPU from its interface before applying the liquid. Even if you're being meticulous, small droplets will separate and run away. So, keep a thin, clean brush handy to deal with them. Don’t spread them or wipe them away; instead, lift them up!

If you have never experienced the sinking feeling of spotting a liquid metal droplet between CPU pins, look at the bottom picture. However, the tiny droplets at the PCB’s edge may be even worse because they're barely visible to the naked eye.

Cleaning with Chemical Agents and a Wire Brush

It's one thing to apply liquid metal. Removing it is an entirely different ballgame. Even popping off the heat sink can be a challenge. It's very easy to pull an AMD processor right out of its locked socket if you're not extra careful. Make life a little easier by starting the process while the processor is still hot, and detach the heat sink by gently turning it left and right. If you roughed both the heat sink and spreader, you're going to be met with resistance. You might be best off mounting a smooth heat sink on a roughed spreader. This combination seems to come apart most easily.

The cleaning agent from Coollaboratory's cleaning set works, but it won't get everything off. Thus, you still have to use the wire brush. Scrape, apply more solvent, wipe, rinse, and repeat. As you might guess, this takes some time.

In the end, you'll probably wind up with two scratched-up surfaces. Luckily, I bought two closed-loop liquid coolers, allowing him to continue testing conventional pastes with a smooth sink.

Coollaboratory Liquid Ultra: Performance Measurements

If you want to know if this solution is worth its high price, the best we can do is answer with a non-committal maybe. Enthusiasts requiring an expensive, hard-to-apply thermal compound to lower Tcase by 2 or 3 degrees Kelvin (which could mean as much as 5 degrees Tcore) might want to consider their build goals. After running our own tests, we can state with some confidence that the supposed improvements of 5 to 7 Kelvin Tcase are overoptimistic. If you see that big of a gain, it's because you weren't doing something right with the paste you were using before. In order to create a more fair measurement, I compared one of the best conventional pastes, the GC-Extreme from Gelid Solutions, against Liquid Ultra. One-eighth of an ounce of GC-Extreme may be good for five or more applications; Coollaboratory's Liquid Ultra allows three, at most. Even without the expensive add-on cleaning kit, you're still looking at the difference between less than $2 per use and more than $4. You're also looking at five seconds of application time compared to three minutes or so. And we still haven’t taken increased risk into account.

Measurement Results

While Liquid Ultra isn’t compatible with aluminum coolers, we're lucky in that the Core 2 Quad Q6600's old boxed cooler sports a copper slug.

It is amazing how well conventional thermal paste fares compared to liquid metal. A more familiar paste sports a lower difference between burned in versus not burned in, but at a mere 1°C ΔT, the Liquid Ultra certainly proves itself in the same league. Whether we run the interval test or the 24-hour stress test, only Gelid's paste manages to get slightly better as time passes.

Asked whether the 1.5 °C ΔT, which the Liquid Ultra holds over Gelid's GC-Extreme with a closed-loop cooler, or the 2.7 °C  ΔT, which it does in the boxed cooler test, are worth extra effort and cost, my personal answer is no. But of course, some enthusiasts swear by the liquid metal. Most folks don't need the stuff; it's really for the overclockers functioning at the very top of their game.

Thermal Adhesives: Arctic Silver And Akasa

Thermal adhesives binds surfaces together, acting as a thermal compound in the process. They're available both as pastes and in pad form, and may be necessary for mounting small heat sinks on memory packages or voltage regulation circuitry. Obviously, conventional pastes don't work in those cases, since the weight of a heat sink causes them to slide right off.

Adhesive pastes have better thermal properties than pads, but they are accompanied by a significant drawback: once thermal adhesive paste cures, you cannot remove the heat sink from the component without damaging something. We've seen too many pictures from folks who've torn off RAM packages or cracked MOSFETs in half. You can try a trick to avoid this: mix thermal adhesive with regular thermal paste. We'll discuss this shortly.

Paste: Arctic Silver Alumina Thermal Adhesive

Arctic Silver's Alumina is a classic among thermal adhesive pastes, but heed the above warning: once applied your heat sink won't come off again. But a similar non-adhesive version is also available, and you can mix about two parts of the adhesive with one part regular paste to achieve a compromise. Your sink shouldn't be affected by gravity or vibrations, but it should still come off if you need it to. After popping it off, remnants of the adhesive will remain on both surfaces, which you'll want to clean with a sponge.

Adhesive Pad: Akasa AK-TT12-80 Thermal Adhesive Tape

It is easier to use an adhesive pad, if you don't mind the compromise in thermal conductivity. But for making sure that RAM packages and MOSFETs don’t get too hot, pads are typically good enough. If you ever plan to change or remove the heat sinks you're attaching, use an adhesive pad rather than paste.

Pastes: Akasa And Alpenföhn

Akasa 455

Model 455 is basically the entry-level product from Akasa. However, it is quite thick and thus not suitable for beginners. A low price cannot make up for the paste’s difficult application.

Akasa Pro-Grade 460

This paste barely differs from the Akasa 455, described above. It is not any easier to use, and the results we measured are only slightly better. Since it's also more expensive than the 455 paste, its purchase is questionable.

Akasa Pro-Grade+ 5022

This is another product from Akasa that costs more than the one we just looked at. While the performance measurements we generated are again better than the previous two compounds, and it is somewhat softer, this is still a thick paste. Warm it up a bit, though, and it can be applied more easily, yielding very satisfactory results.

EKL Alpenföhn Schneekanone

Schneekanone translates to Snow Cannon, which sounds like a whimsical name promising icy-cold CPUs. While your processor certainly won't hit temperatures that low, this paste's thermal performance is still pretty good. However, its price is too high and it's not very easy to use. While it is more expensive than the classic Arctic MX-2, it isn’t any better. Fortunately, enthusiasts in the U.S. won't need to worry about this, since EKL's Alpenföhn Schneekanone isn't available here. 

Pastes: Arctic And Arctic Silver

Arctic MX-2

This classic compound started the premium paste frenzy. It is still a good entry-level choice, too. Inexpensive and easy to use, its thermal performance is in the upper mid-range. And for what you pay, MX-2 seems like it's meant to keep competitors out of the lucrative thermal paste market.

Arctic MX-4

While MX-4 is more expensive than the MX-2, it surprises us by offering only barely better results. This paste may have its strengths, but it's not your best option for high-power applications like GPUs. It's also tougher than Arctic's MX-2, making it more difficult to use, and less attractive to novices. The thermal performance we recorded puts MX-4 into the upper mid-range, but it also doesn’t stand out from the crowd. Fortunately, at $1.75 per gram, it is one of the least-expensive pastes.

Arctic Silver 5

Buyer beware: The brand Arctic Silver is not the same as Arctic. This is one of the few pastes on the market that still sports silver as an ingredient. However, it shows its age and does not keep up with the best pastes out there today. Based on its performance, it seems overpriced.

Pastes: be quiet!, Corsair, And Dimastech

be quiet! DC 1

As with a number of other manufacturers, be quiet! merely puts its label on an OEM product. That doesn't necessarily indicate poor quality, so long as the OEM maintains certain standards. And as it turns out, the DC 1 is a solid paste for beginners, ending up in the upper mid-range. Its handling is similar to MX-2, while its performance is a notch better. While we like the product’s quality, we cannot say the same about pricing. Amazon currently offers 3 g for close to $10.

be quiet! (Paste Bundled with be quiet! Heat Sinks)

We're curious about the pastes that heat sink vendors bundle with their coolers. Since cost is always a factor when it comes to value-adds, we want to know whether it makes sense to toss the included stuff and buy aftermarket compound instead.

In this case, we are positively surprised by the freebie. It should be good enough to complement be quiet!'s coolers, which employ high mounting pressure. Under those conditions, the paste comes in a mere 0.6 °C higher than the DC 1, mentioned above.

Corsair (Paste Enclosed With Corsair Coolers)

This time we're looking at thermal paste bundled with Corsair's coolers. The be quiet! and Corsair compounds achieve similar results, though Corsair's paste is perhaps slightly thicker. It's still pretty easy to use though, and we like what we see from our thermal performance results. In this case, it probably wouldn't make much sense to toss the tube and spend good money on something else.

Dimastech HTX-EE

This compound is one of the most difficult to use, and you should only apply it after warming to 110 °F or so. Its performance results are barely better than what you get for free with some heat sinks, though, and so we're left a little disappointed. We're not saying that this is a bad paste, but for the money you can find better options. This stuff is so thick that we were afraid our heat sink's screws would strip their threads as we tightened them.

Pastes: Coollaboratory

Coollaboratory Liquid Pro

This is the grandfather of liquid metal compounds, and it still holds the record for thermal conductivity. Unfortunately, it also requires the greatest degree of skill to apply. Only experienced, gutsy professionals should use it, and even then, it's both expensive and difficult to remove. Liquid Pro cannot be used with aluminum heat sinks, but can be used with copper- and nickel-plated ones.

Coollaboratory Liquid Ultra

This latest offering from Coollaboratory is somewhat easier to use than its predecessor. But that only means it's a little easier to apply than Liquid Pro. Its thermal attributes aren't quite as good as a result of the different composition. However, Liquid Ultra is still better than any conventional paste. At the end of the day, you'll have to decide if one or two degrees of improved cooling performance is worth the effort and risk. Again, you cannot use this stuff with aluminum heat sinks, though it is compatible with copper- and nickel-plated ones.

Coollaboratory Liquid MetalPad

While these pads can be handled and cut to size easily, the devil is in the details. During burn-in, you have to ensure that the Tcase temperature reaches at least 140 °F, which equates to a Tcore of about 80 °C (176 °F). Some AMD CPUs throttle back at 140 °F, and even our FX-8350 had a hard time holding the required temperature long enough for a successful burn-in. Older AMD processors may be on the brink of meltdown at 140 °F. Without a successful burn-in, however, this product's thermal conductivity is worse than the cheapest paste. It took disconnecting all of my fans to burn the pads in. Naturally, doing this involves some risk.

Coollaboratory Liquid Cleaning Set

High prices and tedious clean-up make Coollaboratory's products very hard for the newbie to use. They're great for experts who want to leave zero overclocking headroom unexploited, though you'll probably find this cleaning kit necessary.

Pastes: Cooler Master

Cooler Master IC Value V1

This is the least-expensive paste from Cooler Master. It's really easy to use, but doesn’t work any better than the random no-name compounds we've tested. While the price is right, performance leaves a lot to be desired. We can only recommend this product for experiments like this one. Fortunately, it's pretty hard to find in the U.S., so there's a good chance you'll never encounter it.

Cooler Master IC Essential E1

This mid-range compound from Cooler Master is approximately twice as expensive as the entry-level product, but is it twice as effective? Our results put the two pastes fairly close together; only in the GPU-oriented test are the differences substantial. But even so, this paste is fairly average, the amount you get is paltry (a mere 1.5 g), and the cost per gram is substantial. IC Essential E1 isn't a price/performance winner. It is easy to use, though.

Cooler Master Extreme Fusion X1

This is Cooler Master's high-end offering, which sets out to outclass the company's older pastes. It achieves this goal, finishing a close second to Gelid's GC-Extreme. Just be sure to warm up the paste before you use it.

Cooler Master (Paste Bundled With Cooler Master Coolers)

Initially, I suspected that the paste bundled with Cooler Master's heat sinks was the same as be quiet!'s, given almost identical syringes. However, spreading the pastes, which are also the same color, revealed different viscosity. That either means we're dealing with distinct products or the same product from widely varying production lots. Variance does happen, particularly when it comes to inexpensive products.

Be that as it may, Cooler Master's paste sports a higher viscosity and winds up trailing be quiet!'s in the test results. It was still better than some pricey aftermarket compounds, though.

Pastes: Gelid Solutions, Noctua, And Phanteks

Gelid Solutions GC-2

We're going to start with Gelid's most budget-oriented solution. Its thermal results are respectable, landing it in the vicinity of Arctic's MX-2, MX-4, and Arctic Silver 5. But it's also noticeably thicker, making it harder to manipulate at room temperature. Nevertheless, this is a solid product that sells for less than $1/g, making it the price/performance leader.

Gelid Solutions GC-Extreme

GC-Extreme is the best thermal paste in our round-up, maintaining a slim lead over the runner-up as long as you're using a heat sink with high mounting pressure. If this compound was a little softer, it'd be even more ideal and wouldn't require warming before application. Heating it up a bit does pay off though, and we recommend it for overclockers and enthusiasts. Due to its high viscosity, it's perhaps less ideal for beginners.

Noctua NT-H1

This paste is almost a classic by now, and it still gets widely recommended. Rightfully so? Our testing reveals that its price/performance ratio is almost as good as Gelid Solution's GC-2, and its thermal parameters are even better. Noctua's solution ends up in the upper mid-range of our contenders, and a low price makes it hard to pass up unless you're a hardcore overclocker.

Phanteks TH-NDC (Paste Bundled With Phanteks Coolers)

The paste that Phanteks includes with its heat sinks contains nano particles of diamond, approaches the thermal performance of Gelid's GC-Extreme, and can be applied as easily, if not more so. It is somewhat similar to Cooler Master's Extreme Fusion X1, but can be applied even by novices. A big shout-out to Phanteks for bundling TH-NDC with its coolers.

Pastes: Prolimatech

Prolimatech PK-1

If we were judging based on price, we certainly wouldn't call this an entry-level thermal compound. But how does it perform? Nano aluminum sounds pretty compelling, but the benchmark results are what matter to us. The PK-1 paste performs well enough, but doesn't blow us out of chairs. Really, it's the price that kills it. There are better alternatives out there, even if Prolimatech's entry-level solution is generally quite user-friendly.

Prolimatech PK-2

Yes, Prolimatech offers more than one thermal paste. The PK-2 compound in the green box sports better performance than PK-1. While it doesn't appear among the front runners, this paste is still in the upper mid-range.

Prolimatech PK-3

Prolimatech’s highest-end paste is more expensive than its other two models. Perhaps that yellow packaging is intended to suggest gold? This is a good thermal compound, but it's not the best one out there. It's also thick like the GC-Extreme, a product that the PK-3 can approach, but not quite reach. Warm this paste up before using it.

Pastes: Revoltec, Scythe, SilverStone, And Thermalright

Revoltec Thermal Grease Nano

No, this isn’t nail polish for female hardware enthusiasts; it's a liquid paste that's applied with a brush attached to the lid. Unfortunately, Revoltec's Thermal Grease Nano doesn't test particularly well. While it's easy to apply and remove, we measured lackluster thermal properties. Enthusiasts will want to stay away. At least it is inexpensive.

Scythe (Paste Bundled with Scythe Coolers)

Our tests with bundled thermal compounds continue. While Scythe's OEM manufacturer is unknown, at least the plastic bag has Scythe's name on it. The benchmark results come back average. They're not particularly good or bad.

SilverStone (Paste Bundled with SilverStone Coolers)

This is what you'll find when you pop open a heat sink from SilverStone. Although the syringe resembles the bundled pastes from be quiet! and Corsair, we come away with slightly different thermal results. The benchmark numbers aren't amazing. Rather, they fall into a range we'd consider pretty average. I wouldn't feel compelling to spend extra on aftermarket thermal compound, though doing so would yield better performance.

Thermalright Chill Factor III

For some reason, I only received a two-gram tube of this paste; the standard tube includes four grams. We generated some fairly average results with Chill Factor III as well. Consider this compound suitable for average users and beginners.

Pastes: Xigmatek

Xigmatek PTI-G3606

Xigmatek’s entry-level paste is called PTI-G3606, and it sells at a mid-range price. Measured thermal performance is acceptable and its ease of use is even commendable. At the end of the day, this is a solid product at a fair price for mainstream hardware enthusiasts. It's simply not what we'd recommend for more hardcore overclockers.

Xigmatek PTI-G4512

Xigmatek's premium thermal compound doesn't even cost more than its entry-level offering. But the trade-off for better thermal performance is higher viscosity. Before using it, warm this paste up. Although it's not really for beginners, we do get a good price/performance ratio out of the PTI-G4512 from Xigmatek.

Xigmatek (Paste Bundled with Xigmatek Coolers)

This is another paste bundled with a cooler we picked up off the shelf. In our tests, the freebie fares slightly worse than Xigmatek's low-end aftermarket stuff, but not by much. It's an average compound that you shouldn't feel compelled to shy away from.

Pastes: Xilence And Zalman

Xilence X5

According to our team in Germany, it appears that Xilence went out of business. Not that it matters much to our U.S. audience; the company's ZUB-XPTP.X5 thermal grease wasn't readily available here anyway. At least we have benchmark data for the compound in our charts for anyone overseas with it. In short, Xilence's X5 is suitable for entry-level systems. Just don't use it on an overclocked processor or a PC in Dubai.

Zalman ZM-STG1

Unfortunately, this one turned out to be a dud in our testing. Zalman's ZM-STG1 is easy enough to apply with a brush, but its effectiveness is sub-par. We'd consider it a notch above Revoltec’s competing compound, but not much higher. Overall, our measured price/performance ratio is a disaster.

Zalman ZM-STG2

The ZM-STG2 paste is priced comparably, but much better than the company's ZM-STG1. That doesn't make this offering good, per se. Surprisingly, both pastes share similar ingredient lists. The ZM-STG2 simply isn't watered down with too much silicone, and it remains tougher, even after burn-in.

Pastes: Just For Fun

Toothpaste

I made the mistake of buying a premium toothpaste with blue stripes through it. A cheap white paste would have probably fared better. Yes, you can use this stuff as a thermal compound, though its long-term stability is questionable and we wouldn't recommend it for overclocking. If all of the shops around you are closed, though, and you want to play a little Battlefield 4 on a new machine, you could probably get by for a couple of days.

Denture Adhesive

If you don't brush your teeth but do live with your grandma, denture adhesive could stand in for toothpaste during those same couple of days. Again, this is not a long-term solution. But then again, neither were grandma’s teeth (or yours, if you don't grab some toothpaste). Be careful with this adhesive. After burn-in, the cooler may stick to the heat spreader and prove hard to remove.

Results: Closed-Loop Liquid Cooler; High Mounting Pressure

I already described our test setup in Thermal Paste Comparison, Part One: Applying Grease And More. What follows is a performance chart on the liquid-cooled system employing high mounting pressure.

Results: Air Cooler; High Mounting Pressure

Likewise, we covered this configuration in Thermal Paste Comparison, Part One: Applying Grease And More. The following chart represents thermal performance of an air-cooled system employing high mounting pressure.

Results: CPU Air Cooler; Low Mounting Pressure

One last time, we covered this configuration in Thermal Paste Comparison, Part One: Applying Grease And More. This chart reflects our air-cooled machine with lower mounting pressure.

Results: Air-Cooled GPU; Medium Mounting Pressure

Our last bit of testing comes from applying these thermal compounds to GPUs, and the results are significantly different from what we saw cooling our CPUs.

The failure of some pastes may be explained by rapid hardening, and a second test with two additional cycles didn't change the outcome. What do we learn from those failures? While value-added pastes may work well with the CPU coolers they were bundled with, they may not behave well under the higher temperatures generated by powerful GPUs, and shouldn't be used with them.

It's Not As Easy As Picking A Favorite...

In the end, it doesn't necessarily matter how much you paid for your paste, or what thermal conductivity its manufacturer claims on the package. More important is the how: your application method makes or breaks this process.

Some of the pastes we tested remain classics, and are even relatively inexpensive. It only follows, then, that we'd caution you against spending big on a brand new paste that'll only make a temperature difference of 1 to 2 Kelvin. If that sort of delta plays a significant role in your overclock, you're courting disaster. Sufficient airflow through the enclosure should ensure that you're never dependent on a particularly high-performance thermal compound.

More hardcore overclockers tuning their systems competitively, or quiet computing enthusiasts who spin their fans down as low as possible for better acoustics might want to give more thought to their paste of choice. Even a majority of power users, however, should focus on a paste’s ease of use, leaning toward the softer compounds. A flawed application typically impacts thermal performance much more than the difference between pricey and value-oriented pastes ever could.

I don’t want to lift any one thermal compound up onto a pedestal, and I'm no fan of award inflation. Sure, I could drop a couple of favorites, but the assessment would be highly subjective because some folks weigh ease-of-use and performance differently. Moreover, a lot of these pastes perform a lot alike. We can still draw several conclusions from our work, though.

• Novices should gravitate to softer pastes and use the "lentil ball" application method
• Experts can warm up thicker pastes, making them easier to apply
• Softer pastes should be used with coolers that attach via low mounting pressure
• Pastes bundled with most CPU heat sinks are good enough
• Different rules apply for GPUs; you need to pick the compound you use on your graphics card very carefully
• While the legends spoken of liquid metals have a basis in fact, they are exaggerated

That’s it from my side. But let me also point out that our Thermal Compound Charts will be maintained with results from any new products that surface. What will I do with all the partially-used syringes and paste packs? Honestly, I don’t know. There's enough of this stuff around to last a lifetime...

Everything You Wanted To Know About Cooling A CPU

I’ve been working on this time-consuming thermal compound test for more than half a year, digging my way through the pastes supplied by Caseking (an online shop in Germany) and the ones we already had on-hand in the lab. Not only does a story like this take a lot of time (it involves nearly 40 products, after all), but it clearly requires a consistent test methodology to make sure the conclusions we draw are sound.

Because we have so many products, we're splitting the story into two parts. The first one delves into the theory and real-world use of thermal compounds, while the second presents all of our benchmark results and the corresponding test setups. 

In part one, we'll cover the thermal properties of CPUs, surface types, background information about various thermal compounds and the methods for applying them, as well as two basic cooler types (liquid and air), along with the issues arising from different mounting pressures. A thermal paste working just fine with one cooler may be a bad fit for another. Therefore, we have to test our thermal pastes on AMD and Intel CPUs with a water cooler, a premium air cooler with high mounting pressure, as well as a more pedestrian push-pin setup, which stands in for the boxed heat sinks you get bundled with most processors.

In addition to CPUs, I also test each paste’s suitability for GPU cooling and assess its viscosity and its ease of use. But let’s start with the basics. What is this primordial goo all about?

The Heat Spreader

When you cut a CPU in half, you notice that the chip (die) itself is much smaller than the CPU package, and thus the die touches only part of the heat spreader. The spreader’s job is to distribute the CPU die’s heat across a larger area, which allows it to pass to the CPU cooler's heat sink.

The drawing illustrates two little-known facts. First, the CPU manufacturer fills the gap between die and heat spreader with a heat-conducting material. While AMD, just like Intel did in the past, fills the void with some kind of solder, Intel now merely uses a thermal compound, which has a higher thermal resistance, but probably saves a few pennies in production. This explains why cooling overclocked Intel CPUs has become more difficult since the Ivy Bridge architecture.

Heat Spreaders, Hot Spots, and Dire Consequences

The drawing also shows that, due to the size difference between CPU die and heat spreader, there are some areas on the heat spreader that will be cooler than the area directly above the die. The area above the die is called the hot spot because it is directly heated by the die underneath. The two images below illustrate what a hot spot is, albeit in an over-simplified way. Reality is not as simple; CPU cores may be loaded differently, and there is also the issue of on-die graphics, which may be more or less active than the processing cores. But let’s just look at the die as a whole and the heat spreader on top of it, viewed from above.

Due to its industry-leading 22 nm manufacturing technology, Intel CPUs have a smaller hot spot than AMD CPUs, and you should take this into account when choosing a heat sink. After all, you need to dissipate heat from the hot spot first and foremost.

Benefits and Drawbacks of DHT Coolers

CPU coolers with exposed, ground-flat heat pipes are the latest fad. They certainly save some money during production, which marketing departments then sell to customers as a performance-enhancing feature. But there are drawbacks to this mechanical design. Consider a cooler with, say, four heat pipes, like the Xigmatek Achilles in the picture below. The outermost heat pipes miss the hot spot completely. Even the two innermost heat pipes only partially cover the narrow hot spot of an Ivy Bridge-based CPU. Adding insult to injury, the cooler typically cannot be turned 90 degrees.

If we could turn the heat sink around we'd ameliorate this situation. AMD CPUs are typically not as affected due to their larger die area and CPU orientation; in most cases, all heat pipes cross the rectangular hot spot. If you want a DHT-based cooler, consider one with five heat pipes for more modern Intel CPUs, and try to avoid designs with large gaps between the ground-flat pipes.

Interim Assessment

Just by choosing an poorly-suited cooler, you can lose more thermal performance than the most expensive compound could ever gain back! But there is more bad news. Let’s take a look at what happens between the heat spreader and the heat sink.

Interaction Of The Heat Spreader And Heat Sink

Uneven Surfaces

A microscope will show you that neither the surface of a heat spreader nor the surface of a heat sink are really smooth. What looks even to the  bare eye is full of pits and grooves.

When you press both surfaces together, only parts of the metal touch each other. Without a thermal compound, air fills the gaps. But air is a bad heat conductor. It's more of an insulator, actually. Thus, without thermal paste, much of the engineering that goes into heat spreaders and CPU coolers is wasted, as heat is only conducted where the metal surfaces touch.

Heat-Conducting Materials to the Rescue! Pastes and Pads

Clearly, the insulating air needs to be displaced by some thermal compound. Obviously, any thermal paste, pad, or liquid metal will conduct heat less effectively than the two metal surfaces involved. So, you want the application to be thin enough to not impose a lot of thermal resistance, but thick enough to overcome the surface imperfections of the heat spreader and sink.

The Differences Between AMD And Intel Heat Spreaders

Convex and Concave Heat Spreaders

To make matters worse, heat spreaders are not merely rough, but due to the way they're manufactured, they aren't level, either. The following diagram exaggerates the problem for the purpose of illustration:

AMD’s heat spreaders are slightly higher in the center and Intel’s have higher edges. From my perspective, AMD's approach is better-suited for cooling. Due to the mounting pressure of the CPU cooler, the thermal compound is thinnest where most of the heat needs to be transferred. Thus, Intel CPUs deserve perhaps a touch more thermal paste, and you should take care that no air gaps form in the center.

How Thermal Paste Spreads under Pressure

The following animation illustrates how thermal paste escapes to the sides when pressure is applied. Later, we’ll discuss the relationship between a paste’s fluidity (how "liquid" it is, the opposite of viscosity) and the maximum mounting pressure in detail. For now, let’s just say that a paste with low viscosity is more suitable for low-pressure mounting methods, like Intel’s push pin method, than a "hard" paste.

The technical specifications of a thermal paste’s thermal resistance do not necessarily predict its real-world performance for a specific combination of CPU, paste, and cooler. A good heat sink can be crippled by a mismatched thermal compound. A good match between cooler and paste can achieve more than just blindly choosing an expensive thermal compound.

Choosing The Right Paste: More Than A Matter Of Price

Because thermal paste is a high-margin product, the market is crowded. While the exact composition of most products is a well-kept secret, a Google search makes it pretty easy to get a list of typical ingredients. The upper temperature limit is typically 150 °C, though some pastes claim to withstand up to 300 °C or more.

The composition of a paste determines its thermal conductivity, its electrical conductivity, its viscosity, and its durability. But what is a paste really made of? Basic compounds consist of zinc oxide and silicone as a binding agent. However, such simple combinations are barely sold anymore. Most vendors start with these ingredients and add other materials, like aluminum. Case in point, the Prolimatech PK1 sports 60-85% aluminum content, 15-25% zinc oxide, and 12-20% silicone oil, as well as an anti-oxidation agent. Some ingredient lists are more mysterious. For instance, the one printed on be quiet!'s DC 1 syringe ambiguously specifies 60% metal oxide, 30% zinc oxide (wait a second; since when is zinc not a metal?), and 10% silicone.

Some pastes, like Arctic Silver 5, even contain silver. Other pastes are based on graphite, like the professional-grade WLPG 10 by Fischer Elektronik, forego the silicone, and claim very high thermal conductivity (10.5 W / m·K), but they are more difficult to apply and are typically electrically conductive. There are also pastes that employ carbon nanoparticles, though they're not suitable for most enthusiasts due to their electrical conductivity and price. The number of copper-based pastes on the market has shrunk, but if you search, you can still find a few.

I leave the more exotic thermal coupling solutions like liquid metal and metal pads for the second part of our tutorial. Applying these electrically conductive products is not without risk, and I don’t want to confuse anyone with a detailed discussion of them at this point. Let’s just say that they're for expert use only, and you'll want to satisfy a few prerequisites prior to applying them.

All pastes share one thing in common: regardless of their composition or price, they all fall short of heat sinks and spreaders with regard to thermal conductivity. Thus, a thermal paste is always the weakest link in the cooling chain, regardless of its price!

Applying Thermal Paste, Part One

A Philosophical Debate: The Application Method

It’s tough to pick a technique for applying paste. Any method only works well if paste quantity and viscosity is absolutely correct for the particular application. In light of the hot spot discussion, however, we believe that smearing paste on the whole CPU is quite pointless and a thing of the past. Instead, we want to focus on the particularities of the CPU, its heat spreader, the heat sink, and the mounting method (in particular the mounting pressure).

Brushes and Low-Viscosity Pastes

Liquid pastes like the Revoltec Thermal Grease Nano can be applied with a brush, and are consequently the easiest to use. However, low viscosity comes at the price of a high silicone content, which impacts thermal conductivity. These pastes typically fall to the bottom of our performance charts. When you try to apply semi-liquid pastes by brush, typically you wind up with too much, and that isn’t optimal, either.

Drop, Sausage, or Wall Painting?

In my opinion, spreading paste on the entire CPU is too tedious and runs the risk of applying too much material, or even causing air pockets. Furthermore, some pastes simply do not want to be smoothed. The more you try to even the surface out, the more it tears open.

Trying to spread a high-viscosity paste with a credit card is a fool’s errand. You'll waste a lot of time and won’t achieve a thin, smooth layer. Yes, you can try to put a latex glove on your hand and use your index finger. But even with this method, the risk of applying too much paste is significant, especially if you have no practice. The higher the viscosity, the less successful you can anticipate being trying to "paint the wall".

A Strip of Paste

When you imagine CPU die under the heat spreader, it may seem smart to put a strip of paste over that area. But don’t apply too much. Otherwise, the paste will ooze out on all sides. If your paste is electrically conductive, you can almost be assured of hardware damage.

When you apply the paste strip frugally, the result is better. Don’t worry too much about bare spots. The edges of the heat spreader don’t contribute much to thermal transfer anyway. If your cooler sports a back plate and applies lots of mounting pressure, the paste will spread further. As a rule of thumb, the lower the viscosity of the paste and the higher the heat sink's mounting pressure, the more your compound of choice will spread.

Applying Thermal Paste, Part Two

The "drop" or "blob" method can be used by both newbies and enthusiasts, and it even works with high-viscosity pastes, assuming you are using a quality cooler that applies plenty of mounting pressure.

Don’t apply too little paste for fear of overdoing it. The compound might end up not covering the hot spot, hurting thermal conductivity and leading to an overheated CPU.

Take the type of cooler into account, too. An aftermarket heat sink with a back plate, which is screwed down, can tolerate less paste than AMD's "hook a clip and flip a lever" or Intel's "four push-pin" sinks. When you use pastes with higher viscosity, you want a cooler able to apply more pressure, and it's alright to use more paste. Of course, when we say more, we mean a little, not an extra-generous slathering.

The picture above shows a near-optimum spread; we wound up with a thin layer that completely covers the die. Since it didn’t reach the edges, we know we didn't use too much paste, and that it wasn't applied too thick. If you know how large a pea is, beware of literally using a pea-sized blob. A paste ball about 1/10” to 1/6” in diameter should be enough; don’t use more than that! We're talking about a lentil-sized ball here.

Last But Not Least: Don’t Panic!

CPU manufacturers also believe in a less-is-more philosophy, as evidenced by their boxed coolers. For instance, AMD’s heat sink only touches about two-thirds of the heat spreader. The stencil-printed paste sports a high viscosity. It's almost solid, and it doesn't spread outwards (the sink's mounting pressure is relatively low). But this method obviously gets AMD’s blessing.

Why do I mention this cheap boxed cooler? To allay fears and to encourage a healthy do-it-yourself sprit. Yes, two decades ago I also had my doubts about mounting aftermarket CPU coolers. But I encourage you to try it with an ounce of preparation, a sprinkle of can-do attitude, and a pinch of carefulness. Nothing will go wrong.

Why Do We Test Each Paste In Four Scenarios?

In choosing four test platforms, I incorporate feedback from our valued readers. For instance, you wanted to see us take the cooler mounting pressure into account. We're skipping the LN2-based testing and focusing on scenarios you'll encounter in the real world. For example, we're using popular pre-assembled water coolers that should ensure heat sink temperatures below 60 °C (140 °F), premium aftermarket air coolers with back plates that should demonstrate high mounting pressure, and a run-of-the-mill budget cooler with push-pin mounting (that'll give us limited pressure). Stock coolers like that let the CPU get above 60 °C/140 °F (AMD) and 80 °C/176 °F (Intel).

Depending on viscosity and composition, not all pastes are a good fit for every application, nor are they all well-suited for novices. This warning also applies to replacing the heat sink on your GPU, and we'll discuss that separately below.

First, let's take a look at the three systems I used to test each thermal compound.

Testing Thermal Paste on a Graphics Card

This is a somewhat sensitive topic, and for safety reasons I excluded electrically conductive or liquid metal pastes from my testing. Since GPUs don’t have a heat spreader, but allow the cooler’s sink to directly sit on the die, I didn't want anyone to risk a short circuit.

I also used an older graphics card, which was convenient to test with. Its cooler was mounted using four screws and its fan speed could be dialed in to a constant value. Furthermore, I figured that an older card would be more tolerant of the higher temperatures I'd see. After all, we didn't want a cheap paste to destroy an expensive, current-gen board. Fortunately, the GPU die size and surface temperature are still comparable to modern mid-range cards.

Test Cycles, Test Duration and Settings

I should also explain how I took my measurements. Because the digital temperature sensors built-in to modern CPUs only give us uncalibrated Tcore values, I used the old way of measuring die temperature with a thermal diode under the heat spreader. The processors in this story still use soldered-on spreaders, so this value should be fairly accurate. I'll report the difference between Tcase and the room temperature, since that latter figure wasn't as constant as I would have liked through all of the benchmarking.

For the graphics card, I used the temperature as the GPU reported it. That number wasn't influenced by minor changes in room temperature.

Get Ready For The Thermal Compound Benchmarks!

Tom's Hardware's Thermal Compound Charts and a Part Two Preview

Based on those four setups, I tabulated the test results of 20 pastes and published them to our Thermal Compound Charts. These benchmarks help determine how much experience a given product requires, which application is best suited to each compound, and whether they're appropriate for use with graphics cards.

The second part will also discuss liquid metal offerings and various thermal pads, both of which are special cases. Finally, all tested products are introduced and pictured. In other words, there are not only charts and tables, but also a brief verbal assessment of each and every tested product. Yes, you'll even get a few purchase recommendations.

Does "really expensive" always translate to "really good"? Part two of our exploration will answer that question. 

As the name suggests, the heatpipes in a HDT cooler are placed in the base of the cooler and gaps will normally be present between the base and the heatpipes. This results in a lower surface area of contact when the base touches the CPU which will in turn reduce the cooler's thermal efficiency. To solve this problem Xigmatek's Xi-3 thermal compound was designed specifically for HDT coolers and features smaller, more dense particles. The Xi-3 is rated at 104 Pa·s, specific gravity at 2.5 g/cm³, 9.1 W/mK thermal conductivity and features an anti-bleed composition.

As with most other compounds on the market, the compound is non-electrically conductive and will be sold in a 4 g syringe for a currently unknown price.

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The new DC1 thermal compound is a material with a particular mix which allows for a very wide range of operating temperatures. The compound has a working temperature that ranges from -50 °C to 150 °C. The theoretical thermal conductivity of the material is 7.5 W/ mK, and according to be quiet!, this should give its new thermal paste a thermal advantage over cheaper, conventional materials.

The material's composition is 10 percent silicone compound, 60 percent metal oxide, and 30 percent zinc oxide compounds.

The DC1 thermal paste comes in a tube syringe and carries 3 grams of material. Included with it is a small spatula so that users can spread the compound evenly if they believe that this is an effective method.

be quiet!'s DC1 thermal compound is already in stores for a price of €6.49.

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Sony recently demonstrated a thermal sheet, which the company claims is matching paste in thermal performance, but besting it in lifetime.

Called EX20000C, the sheet was shown at Techno-Frontier 2012 in Tokyo last week, where the paste kept a CPU at a stable 53 degrees Celsius, and the thermal sheet kept it at 50 degrees Celsius. There was no information on the processor used in the demonstration.

According to Sony, the sheet is between 0.3 and 2.0mm thick and features a thermal resistance of 0.4-0.2K·cm2/W. Sony has offered thermal pads for some time, such as the EX50000, which, however, cannot match the performance of thermal paste.

"The EX20000C is the first sheet that has such a low thermal resistance," the company said, according to an article published by Tech-On.

There was no information when the EX20000C could become commercially available.