The Skylake-X Mess Explored: Thermal Paste And Runaway Power
Manual Overclocking & Conclusion
The Motherboard Manufacturers’ Duty
Ultimately, we’re looking at power consumption numbers similar to some high-end graphics cards when we start messing with Skylake-X. AMD’s FX-9590X doesn’t even come close to these results, if that means anything to you. This means motherboard manufacturers need to start spending money on better components and cooling solutions to take care of those components. Otherwise, long-term reliability will be hard to guarantee. Ultra-durable and military-class components don't have to be exclusive to top-end products; they can bolster mid-range platforms, too.
Motherboard manufacturers could have and should have known that Intel's Skylake-X CPUs would consume power indiscriminately, in spite of the company's laughably low TDP specifications. Everyone has access to Intel's datasheets, not just us.
Different motherboards will be affected to different degrees by our findings, and the one we tested isn't a flagship model by any means. You shouldn't generalize our results to mean there's an impending VRM-related disaster hanging over the heads of all Skylake-X owners. Boards from every manufacturer across a number of price points need to be tested before such a claim can be made. What we do know is that, although the problem originates under Intel's heat spreader, fault is also found with motherboard manufacturers as well.
We already have a high-end motherboard on its way from the same manufacturer, and we'll report our findings after running the same battery of tests.
Overclocking For Power, Not Frequency
Although we ultimately wanted to explore the CPU's and VRM's cooling problems, we were also curious about Skylake-X's remaining overclocking headroom. Rather than targeting specific clock rates, though, we systematically pushed our Core i9-7900X to 250W and then to 300W. That's all its technical specifications allow for, so that’s where we stopped.
Observation #5: We aren't here to destroy our hardware. Enthusiasts need to decide on their own if they're willing to risk $1000 components. Power users on the overclocking circuit typically have processors provided to them, so a single CPU isn’t something to lose sleep over. We, however, along with most folks only have one sample to work with. Failure would be far more devastating. Technical specifications and limits are there for a reason, and in this case we're honoring them.
Let’s start with the massive 250W, which Intel's Core i7-5960X reached at 4.8 GHz back when we reviewed it. Core i9-7900X gets there at 4.5 GHz under Prime95, and at 4.6 GHz with LuxRender in a console loop. Other applications yield better results, depending on their workloads.
Intel’s Core i9-7820X doesn’t really do any better: it’s separated from the larger 10-core processor by only 20W when performing the same tasks. If you're overclocking this way, pay close attention to wattage and adjust the clock rates and voltages via trial and error, depending on the applications you use.
250W & The Limits Of Normal Water Cooling
In our scenario, we occasionally hit the 270W mark, which probably represents this specific motherboard’s limit. In other words, MSI’s X299 Gaming Pro Carbon AC stays approximately 30W below the maximum wattage allowed by Intel’s technical specifications. The problem is that most custom water-cooling setups aren't able to keep the die and package cool enough to prevent throttling. Even with a water temperature of 30°C, it wasn't possible to run under load for more than 10 to 15 minutes without thermal issues.
The CPU throttles before the motherboard’s VRM has a chance to hit 100°C. This means that all of the flashy plastic parts on top of the VRM are basically useless, since the CPU throttles before they can do anything. Once again, here’s the video to go along with the graph:
Intel’s Limit: 300W & The Mild Scent Of Disaster
Now, can we hit the 300W mark without our system dying a fiery death using our trusty Alphacool Eiszeit 2000 Chiller? To make a long story short: yes, we can...for about 10 minutes. After that, the voltage converters hit 105°C and the CPU’s frequency drops to 1.2 GHz with a power consumption of 70W. That’s enough for the components to recuperate quickly, after which the whole sequence starts over, resulting in an endless loop.
So close, but no cigar. Then again, who else out there uses an Alphacool Eiszeit 2000 Chiller? Most folks won't be able to push their system to the brink of death like this without delidding their processor first. Even with our high-end cooling solution, the Tpackage measurement exceeds 100°C, while the cores run at 94°C and up. This can’t be called sufficient cooling by any stretch of the imagination.
Our video shows the motherboard and its hot-spots once again. In spite of the 105°C you'll see in a few places, none of the components are in danger, since none of the ones that have a temperature limit below this number are affected. That’s at least something.
At least we can rest easy knowing that few power users will ever take their Skylake-X CPUs this far. And if your job involves testing high-end hardware, you shouldn't have a problem locating a suitable motherboard able to handle the heat.
Conclusion
So, what’s the bottom line? Intel is pushing the envelope once again with a factory-overclocked Xeon processor doing double-duty as a high-end desktop masterpiece. We're getting the sense, though, that the revered Core architecture can't be pushed much further. Everything works well enough this time around, at least. And if Intel hadn't chickened out and put thermal paste between its die and heat spreader, there might have been a happier ending for everyone involved in this story.
As it stands, even a custom water-cooling loop has to throw in the towel at 250W, long before most motherboard voltage converters hit their limits. Under normal operating conditions, the CPU, and not the motherboard, always throttles first.
Nevertheless, motherboard manufacturers aren’t blameless when it comes to the issues we encountered at launch and continue battling today. Using more thermodynamic expertise and less flashy plastic pieces would have paved the way for brawnier motherboards at the same price points. This would have ended the speculation before it even started. Anything designed to be just good enough always leaves you with a bad aftertaste, particularly since you never know when you might need a little extra headroom.
[Editor’s Note: We reached out to Intel for commentary back in March after a number of readers speculated about Intel’s choice of thermal paste on Kaby Lake, and in response to our article De-Lidding And Overclocking Core i7-7700K With Water And LN2. We did not receive any technical or marketing explanations at the time, but we have followed up again related to the Skylake-X issue, and we will update this article if and when we receive a reply.]
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With 7900X which is still built using 14nm fabrication process, there is no in hell you are going to be fine with temperatures on overclocked 10/20 cores. That's just too many of them to keep them cool.
If someone gets 10/20 CPU i would not push more than 4Ghz. That is a max realistic clock speed for such CPU, with 8 Core you will be better but i'd say the best thing to buy is actually 6/12 Core which can easily run at @4.5Ghz.
People don't play Prime or any other similar >Mod edit: keep it clean<test. People game, do programming, stuff where you will never see CPU showing overheating issue. And again keep 10/20 at 4.0Ghz max. Honestly you won't gain a thing running at 4.4Ghz.
What's wrong with using Prime? It does a good job of testing the thermal limits of a CPU. You wouldn't test the limits of a weight lifters strength with 5 pound dumb bells. You need to go all out.
You say that the author of this article approached this problem with a wrong assumption. Do you think that there's nothing noteworthy of Skylake X's thermal performance?
I think this article did a good job of pointing out the glaring flaws of Skylake X. The conclusion is really interesting: "We're getting the sense, though, that the revered Core architecture can't be pushed much further." That gives me chills. I never thought I'd see the day when Core hit its limits.
It's a chilling conclusion indeed. It all points out to AMD's multi-die, multi-ccx architecture of Ryzen Threadripper being supperior to Inte's Core on all counts.
BUT (you knew that was coming
It seems off-kilter to focus/blame board components and OEMs at the top of your conclusion page, and not really Chipzilla, while noting Sky(lake-X)-rocketing heat/power beyond that of the previous-gen 32nm AMD FX-9590 (constantly derided since its introduction as a power-hungry 'heater').
Know what I mean, Vern?
edit: How could I have misquoted Earnest!
I know its petty, but isn't the line, "Know what I mean?" We're talking Jim Varney, right? Haha.
I agree, they should be called out when form causes a hit to function. I didn't find it harsh at all. Motherboard makers are all enamored right now with shiny pretty and are loosing sight on quality. I don't care if it has LED's or looks "cool" but never should that be at the expense of the motherboards main function.
Because it is unrealistic, and finding thermal limit is just pointless. Go and read Intel specs sheet and tells you about this processor thermal limit. We really don't need any test to show such thing. Tomshardware spent pages of writing something pretty much everyone knew about if you were to read Intel specs. And even if you did not logically anyone can conclude that using same 14nm fabrication process won't play in favor in term of overclocking and heat.
Again 10/20 is a lot of cores and to cool that with 4.0 Ghz+ clock speed, good luck with that.
You people think that AMD Thread Ripper will run cooler, it will with 2.4Ghz clock speed. Seriously i had chance to play with every iteration of Xeon and AMD counter part CPU and you people have no idea of what you are talking about. 18 Core Broadwell-E or Haswell-E CPU for example is hell of task to cool down therefore those CPU run <3.0Ghz speed. We didn't hit any limit with Core CPU, but with what's possible using 14nm fabrication process. The fact that you can even overclock 10/20 to 4.4Ghz with such core count and complexity CPU package itself carries is AMAZING compared to AMD Ryzen which can't hit anything above 4.0Ghz with rather high temperature.
You people get your fact straight.
The bodybuilder analogy is idiotic. The prime95 equivalent would be to require grocery stockers to bench 500lbs as part of the hiring process to demonstrate the strength necessary to lift grocery products on the shelf. They will NEVER have to lift that much making it a meaningless and unrealistic test.
Once/If Threadripper is able to clock higher and have a faster IPC, then AMD can talk about being superior. Looking at the leaked specs so far, neither appears to be true. While it's great that AMD is back in the game again and finally giving Intel competition, they are no means superior outside cost/value and core count.
To give a comparison, Threadripper supposedly will have a tdp of 125-155w, with the highest topping out at 4.1ghz boost. The 10 core equivalent has a 125w and 4ghz boost.
http://wccftech.com/amd-threadripper-1998x-and-threadripper-1998-processors-x399-x390/
Chances are these will run quite hot as well and are huge in size. These 2 links show the size of the die and coolers needed:
https://www.lowyat.net/2017/133239/computex-2017-noctuas-amd-threadripper-cpu-cooler-massive/
http://www.pcgamer.com/amds-threadripper-is-huge-with-an-equally-large-socket-and-cooler/
Intel's I9-7900x has a tdp of 140w, with a 4.3ghz boost. Their die size is still roughly the same as that of the rest of their core lineup in comparison to Threadripper's monstrous size. The biggest mistakes Intel made was the thermal paste (as the author mentioned) and while not really a mistake; trying to cram too much into a tiny space for their socket.
We will see soon enough on Threadripper. I really don't think they will run hot as you do. They have a large heat spreader with the dies underneath spaced out and should be soldered. This should make for lovely cooling capabilities even with air. The 16+ core parts of AMD and Intel are where it gets really interesting seeing how Intel deals with the heat of a CPU that is 60-80% more cores than the 7900x.
Main board makers at fault for as you stated putting all that plastic bling bling on the boards because they think consumers think it is cool. Only teens and 20 something find that cool the rest of us just want fully working boards that do as advertised out of the box. If the plastic bling bling & RGB lighting effects the board performance it needs to go simple as that.
If those are 5k caps, they'll only last 5000 hours at their rated temperature. Lifetime usually doubles for each 10C under that rating.
These CPUs often end up in entry level workstations. If the intended usage pushes the caps to 75 C, and they are the more common 5k/105C, then conventional wisdom indicates that 10% of the caps should fail by the 40,000 hour mark. In those cases where the CPU is fully loaded most of the time, this will occur 4.5 to 5 years of age. This means that there isn't much room for mistakes in the motherboard layout, case design, or airflow requirements. It's something that potential consumers should take into account if they want to get the most out of this platform.
I'd have to check in more detail to give any estimates for the MOSFET lifetime, but that's another factor to account for if longevity is a priority.
Overaggressive turbo clocks, high power consumption, unacceptable temps, and this is only the 10core...
Since they dropped the price more than they wanted now they cheap out $1 from solder to toothpaste.