After hearing about 5 GHz overclocks from pre-production fourth-generation Core processors (that's Haswell, for fans of code names), enthusiasts were despondent to hear that retail parts would be far less friendly. Angelini even went so far as to poll folks with hundreds of retail processors for his launch coverage in The Core i7-4770K Review: Haswell Is Faster; Desktop Enthusiasts Yawn. The consensus was that stability at 4.5 and 4.6 GHz on air was extremely rare, that most enthusiasts should expect to top out at 4.3 GHz or less using 1.2 V, and that heat is the most likely culprit.
Before we get into the details, let's have a quick look at the nine air coolers we'll be testing in today's round-up.

| LGA 115x CPU Cooler Features | |||
|---|---|---|---|
| Gamer Storm Assassin | Noctua NH-U14S | Phanteks PH-TC14PE | |
| Height | 6.4" | 6.6" | 6.5" |
| Width | 5.8" | 5.9" | 5.8" |
| Rad. Thickness | 2x 2.0" | 2.1" | 2x 2.1" |
| Total Thickness | 6.0" | 3.1" | 6.3" |
| Base Height | 1.7" | 1.8" | 1.6" |
| Assy. Offset | 1.0" Forward | 1.0" Forward | 1.0" Forward |
| Cooling Fans | 1 x 140 x 25 mm 1 x 120 x 25 mm | 1 x 140 x 25 mm | 2 x 140 x 25 mm |
| Connectors | 1 x PWM 1 x Three-Pin | PWM | 2 x Three-Pin |
| Weight | 37 Ounces | 36 Ounces | 47 Ounces |
| Intel LGAs | 115x, 2011, 1366, 775 | 115x, 2011 | 115x, 2011, 1366, 775 |
| AMD Sockets | Four-bolt Rectangular | Four-bolt Rectangular | Four-bolt Rectangular |
| AMD Orientation | Vertical | Vertical | Vertical |
| Web Price | $80 | $75 | $85 |
DeepCool’s Assassin and Phantek’s TC14PE return from our LGA 2011 round-up, ready to prove themselves against the more thermally-constrained Haswell package. The Assassin carries the Gamer Storm logo.

| LGA-115x CPU Cooler Features | |||
|---|---|---|---|
| Prolimatech PRO-GNSS-BK | Scythe Ashura SCASR-1000 | SilverStone Argon AR01 | |
| Height | 6.5" | 6.4" | 6.3" |
| Width | 8.5" | 5.7" | 4.8" |
| Rad. Thickness | 2 x 1.3" | 2.6" | 2.0" |
| Total Thickness | 8.5" | 3.5" | 3.0" |
| Base Height | 1.9" | 1.6" | 1.5" |
| Assy. Offset | 1.6" Forward | None | 1.0" Forward |
| Cooling Fans | Not Included (2 x 140/120 mm) | 1 x 140 x 25 mm | 1 x 120 x 25 mm |
| Connectors | Fan-Dependent | PWM | PWM |
| Weight | 32 Ounces | 37 Ounces | 26 Ounces |
| Intel Sockets | 115x, 2011, 1366, 775 | 115x, 2011, 1366, 775 | 115x, 2011, 1366, 775 |
| AMD Sockets | Four-bolt Rectangular | Four-bolt Rectangular | Four-bolt Rectangular |
| AMD Orientation | Both | Both | Vertical |
| Web Price | $80 | $50 | $35 |
Prolimatech sent a pair of fans and alternative clips with its $80 PRO-GNSS-BK, pushing the as-tested configuration to $125.

| LGA-115x CPU Cooler Features | |||
|---|---|---|---|
| Thermalright Archon SB-E X2 | Xigmatek Night Hawk Frostbourne | Zalman CNPS10X Optima | |
| Height | 6.8" | 6.3" | 6.1" |
| Width | 6.1" | 4.8" | 5.1" |
| Rad. Thickness | 2.1" | 2.0" | 2.5" |
| Total Thickness | 4.1" | 3.0" | 3.4" |
| Base Height | 1.6" | 1.4" | 1.4" |
| Assy. Offset | None | 1.0" Forward | 0.9" Forward |
| Cooling Fans | 2 x 140 x 26 mm | 1 x 120 x25 mm | 1 x 120 x 25 mm |
| Connectors | 2 x PWM | PWM | PWM |
| Weight | 47 Ounces | 22 Ounces | 24 Ounces |
| Intel Sockets | 115x, 2011, 1366, 775 | 115x, 2011, 1366, 775 | 115x, 2011, 1366, 775 |
| AMD Sockets | Four-bolt Rectangular | Four-bolt Rectangular | Four-bolt Rectangular |
| AMD Orientation | Vertical | Vertical | Vertical |
| Web Price | $80 | $50 | $30 |
Thermalright adds a second fan to its Archon SB-E, which now supports smaller LGA and even AMD’s sockets. Zalman updates its previously-reviewed CNPS10X in this Optima-version.
One small detail that went largely overlooked in that already-mentioned launch article was voltage. Our source, whose retail processors were topping out in the 4.3 to 4.4 GHz range was only using 1.2 V to maintain low heat levels. After all, he's selling Haswell-based systems that need to remain stable through multiple years of warranty coverage. Meanwhile, I was pushing my press sample harder with 1.3 V. Was he being overly cautious? Was I too aggressive? Could my cooling situation really be that much better? Or might differences in stress testing account for everything?

One of our contacts recommended LinX to test the Hasewell architecture's advanced AVX 2.0 pipeline, suggesting it'd yield temperatures significantly higher than Prime95. Although we didn't see the delta he did, LinX does get somewhat hotter. It's even more taxing than the Intel stress test I used in our first Z87 Express motherboard round-up.
Switching to LinX broke my previous overclocking thermal limit at 1.3 V, forcing a drop to 1.25 V. The reduced voltage in turn dropped my “ragged edge” maximum to 4.6 GHz. Rather than trying to perfect that 4.6 GHz and worry about what might happen to it in the future as the sample started degrading, I informed today's invitees that we would test at 1.25 V and 4.50 GHz.

I also informed invitees that any cooler that allowed our CPU to bump the processor’s 100° Celsius thermal limit would need to be disqualified from this article’s conclusion.
Like the source Chris Angelini queried for his launch article, I could have also used 1.2 V to play it safe and limit my own overclocks to 4.4 GHz. But why would I do that? If I use my old MUX-120 review sample as a starting point, shouldn’t all of today’s top coolers be better?
Depending on where you look, you’ll find the Assassin CPU cooler sold under the DeepCool or Logisys brands, and perhaps as part number MC8000. The one thing both companies share is the Gamer Storm logo on the product and its packaging.

DeepCool didn’t need to specify any changes to the Assassin’s installation kit, since the mid-sized LGA mounting pattern is the same all the way back through the 1156, 1155, and 1150 interfaces. It’s also compatible with older LGA 775 and LGA 1366 boards, as well as the more modern LGA 2011. Its mounting kit is even able to replace the four-bolt bracket on AMD’s Socket AM2 through AM3+.

A decorative plated finish prevents oxidation of the Assassin cooler’s polished copper base, which comprises eight heat pipes to connect its pair of radiators.

The Assassin uses Intel’s LGA support plate as a spacer, preventing contact between its metal parts and any motherboard components, such as what we experienced in our recent System Builder Marathon. Rubber locating clips keep mounting studs in position without any crushing risks.
After positioning mounting screws on the cooler support plate (as shown on the previous page), the screws are inserted through motherboard holes (front-left in photo below), topped with plastic spacers (rear-left), topped again with mounting brackets (right), and then secured with nuts (right-rear).

A cross brace secures the Assassin cooler’s base to mounting brackets, using factory-installed spring-loaded screws to assure proper contact pressure.

The Assassin includes enough clips to install three fans and, unlike many competing products, the middle fan can be clipped to both radiators. Doing this reduces flex between the radiators.

Unlike its monster-sized D14, Noctua’s NH-U14S uses a single radiator to reduce space, cost, and weight on the motherboard. Those sound like laudable goals as long as performance remains satisfactory, and the company offers an even-smaller NH-U12S for builds in more compact spaces.

A superbly-machined, polished, and plated base are intended to give the NH-U14S the best possible contact with CPU heat spreaders.

Designed specifically for mainstream platforms, the NH-U14S installation kit includes only a single socket support plate that fits Intel’s LGA 1150, 1155, and 1156. A second set of AMD-specific brackets use the motherboard’s integrated support plate.

The LGA support plate fits around Intel’s socket plate and rests upon the board, using a thin insulating sheet to prevent shorts. Though we expect this solution to suffice on microATX and ATX motherboards, contact pressure on nearby components could be a problem for certain mini-ITX-based solutions, as seen in our recent System Builder Marathon.
Studs on the Intel LGA support plate push through mounting holes from behind the motherboard (front-left, photo below) and are then topped with plastic spacers (front-right). Mounting brackets are next (rear), followed by nuts (rear-right).

A cross brace is factory-installed to the top of the NH-U14S base, as are a pair of spring-loaded hold-down nuts. These engage studs on the mounting brackets, and the springs assure appropriate pressure between the cooler base and CPU heat spreader.

Noctua also installs the NH-U14S' fan at the factory, though we removed it to access the front mounting nut in the above photo. It’s now clipped back into place.

The PH-TC14PE returns in red trim for our LGA 1150 cooling comparison, giving us a chance to see how a huge cooler that nearly topped our LGA 2011 charts copes with a tiny-but-hot overclocked Haswell die.

Oxidation-resistant electroplating in the PH-TC14PE’s finely-machined base is nearly translucent to provide optimal contact with the CPU’s heat spreader.

Relying on the original support plate for AMD’s Socket AM2 to AM3+ installation, the cooler’s universal Intel-compatible support plate uses the board’s smaller integrated socket plate as a shim. Thick rubber spacers minimize support plate warping, while preventing short circuits or crush damage on boards that have components near mounting holes.

Screws installed into the PH-TC14PE support plate (previous page) poke through from behind the motherboard (front, photo below). Plastic spacers (left-rear) support mounting brackets (right), which are then secured with screws (right-rear).

Phanteks adds a center screw to its cross bracket so that it won’t fall off when you install and remove the heat sink. Nuts on each end of the bracket engage studs on the mounting brackets, and springs on those nuts assure proper contact pressure between the cooler base and CPU heat spreader.

Phanteks includes enough clips to mount up to three fans, and bundles two fans in the PH-TC14PE’s stock configuration. The cooler base is up high enough to clear DIMMs up to two inches tall, and fans can be moved up or down on the sink for full memory clearance or added voltage regulator ventilation.

Maker of the famous Megahalems heat sink, Prolimatech decided to change things up for its Genesis design by combining the benefits of both down- and cross-draft cooling. We received the even more exclusive Black version of this design.

Rather than take the typical one-size-fits-most approach, Prolimatech sells its heat sinks without fans. The Genesis includes clips for both 120 and 140 mm third-party fans (standard 25 mm thickness), and Prolimatech even offers a few fan models under its own name.

Most unusual of its fan products is Prolimatech’s 15 mm-thick 140 mm model. The firm sent a pair of these ($20 each), along with the special clips needed to use this nonstandard thickness on the Genesis ($5), adding a total of $45 to the cost of this $80 sink.

Oxide-resistant electroplating assures excellent contact between the Genesis’ finely-machined copper base and your CPU’s integrated heat spreader.

O-rings secure nuts to Prolimatek’s Intel-compatible support plate. The plate uses Intel’s socket backing plate as a spacer, and the nuts have shoulders to prevent pull-through. Though setup requires a little dexterity, the result is a mount that doesn’t create any clearance issues with nearby components.
Double-ended studs (left-rear in photo below) secure the support plate’s nuts (photo forward) to the motherboard, while additional nuts secure mounting brackets (top-right) to the studs.

Secured with ordinary screws, a cross bracket presses the Genesis cooler’s base against the CPU’s integrated heat spreader.

Your choice of fans are then clipped onto the heat sink’s twin radiators. This design allows one of the fans to cool the CPU, DRAM, and motherboard components simultaneously.

Worried about DIMM clearance? We’re not. Tall modules work fine. Rather, the parallel radiator’s primary drawback appears to be that it blocks DIMM access, complicating memory upgrades and diagnostics.

Sporadic availability has lead to wild price fluctuations in Scythe’s latest products, with the Ashura selling for anywhere between $50 and $80 when we can find it. Hopefully the firm stabilizes formerly-productive partnerships with major U.S. distributors.

The Ashura is, after all, one of the least expensive high-end coolers in today’s round-up, owing that description to its oversized radiator, 140 mm fan, and finely-machined copper base.

Supporting AMD sockets back to AM2 and Intel LGAs back to 775, the Ashura’s Intel support plate rotates to various positions to align mounting holes. Less-than-perfect for boards with mounting-hole crowding, we at least find rubber pads to protect those components from being crushed.

As with most coolers that employ standoffs, the Ashura uses insulated washers to prevent motherboard scratches and shorts. Those washers aren’t attached to the standoffs, however, and must be positioned over the holes first (bottom-left of photo below).

The standoffs (bottom-right of photo above) screw into corresponding holes in the under-motherboard support plate and are topped with mounting brackets (top of photo). Screws (top-right) hold the mounting bracket in place.

A cross brace installs over the Ashura’s base, screwing to the mounting brackets to hold the base tightly against the CPU.

The fan can be clipped onto the heat sink at various heights above the motherboard, providing either added DIMM clearance or added airflow under the fins, which can reduce a motheboard’s voltage regulator temperature.
SilverStone targets the Argon AR01 at value seekers, who can find the entire package for $35 at various sites. Though the modest price is matched by moderate specifications, budget-sensitive enthusiasts might find another advantage in an installation kit the lets it fit multiple platforms.

A proponent of direct contact with its heat pipes, SilverStone selected the three-pipe AR01 for this round-up specifically because of the Haswell core’s small heat spreader. Using the company's larger AR03 as an example, the outer pipes on that design don't make contact with the CPU. SilverStone does, however, increase the diameter of its AR01 pipes to 8 mm, up from the AR03’s 6 mm.

SilverStone’s machinists do a great job of leveling the base to maximize contact.

The AR01’s support plate features three holes on the Intel side to line up with LGA 775, 1150/1155/1156, and 1366. It also flips over to replace AMD’s default four-screw support clip system. Both sides use a thin, hard insulation layer to prevent shorts, though we’ve seen places where those wide tabs won’t fit.
Insulated washers (bottom-center of photo below) protect the motherboard from bracket standoffs (right side of photo), which are screwed into the motherboard support plate. Mounting brackets top these standoffs, and are secured with nuts (top of photo).

Also secured by thick nuts, a cross brace holds the AR01’s base tightly against the top of the CPU. Cross cuts provide for compatibility with both Phillips and flat-head screwdrivers, in addition to an included wrench.

Synthetic rubber straps then connect the fan to the heat sink, preventing the transmission of vibrations. Unlike the rubber rivets used by some competing brands, SilverStone’s straps snap in from the side for easy removal.

We’ve seen Thermalright’s extra-wide heat sink in a previous review, but the new version includes an updated installation kit in addition to its dual-fan (X2) name change.

The Intel support plate is now separate from the AMD plate, and includes a couple of special features to eliminate any conflicts with nearby motherboard components.

The bolts slide, with only a small portion of the bolt pressing against the board. That eliminates most of the on-board component conflicts experience with many competing products.

The bolts are also topped with insulating plastic washers, which add even more space for components that could be close to the mounting holes.

We still get the quality of a smoothly-machined copper base, which transfers heat to all eight heat pipes regardless of our processor’s small contact area.
Intel’s square LGA cooler mounts allow any cooler to be rotated 90°, but AMD’s rectangular bolt pattern doesn’t. Thermalright’s cooler bracket is notched on only two edges for AMD mounting, so the firm adds extra mounting studs to enable the same mounting flexibility on all compatible platforms.

Standoffs with factory-applied insulating washers screw into the support plate under the motherboard, and are then topped with the mounting bracket. The mounting bracket is secured with nuts.

The X2’s revised cross brace includes factory-installed mounting nuts on each end and a pressure-adjusting screw in the center.

After attaching the cross-brace to the mounting bracket, the pressure-adjusting screw is tightened to the specifications outlined in Thermalright’s manual. The lack of any torque indication on the wrench requires builders to use their best judgment.

User-applied adhesive rubber tabs reduce the transmission of fan vibration to the heat-sink’s cooling fins. We had to move these a few times to find the best position.
If you like Xigmatek’s latest cooler, we wish you the best of luck finding it. After all, the company isn't big on model names, and online vendors are labeling this cooler by various versions of its extra-long name. What we have here today isn’t a failure to communicate, but instead a limited-edition white version of its Dark Knight II.

Xigmatek favors direct contact between its heat pipes and the CPU's heat spreader. It uses three fat pipes to achieve good coverage across the Haswell-based CPU's fairly small spreader. Its sanded finish is far smoother than it appears, and fills nicely with the tiny particles of silver-based thermal compounds.

A universal plastic support plate rotates into various positions to line up with Intel’s three LGA bolt patterns (775, 1150/1155/1156, 1366), and flips over to replace AMD’s four-bolt rectangular retainer. The wide tabs of this design work with most motherboards, though we’ve seen exceptions.

A fiber washer (bottom of photo below) prevents standoffs (right of photo) from scratching your motherboard as they're screwed into the support plate beneath the board. Mounting brackets top the standoffs and are secured with nuts (top of photo).

Chrome-plated spacers prevent the final set of mounting nuts from gouging an aluminum cross brace. The nuts are cross cut to support both flat-head and Phillips screwdrivers, in addition to an included wrench, and squeeze the base of the cooler tightly against the top of the CPU.

Rubber rivets secure the Night Hawk’s fan to heat sink fins, while preventing the transmission of vibrations.

Like one of its competitors, Zalman adds a channel down the center of its CNPS10X Optima heat sink to direct air, rather than let too much of the fan’s pressure escape from the sides. The cooler also features a universal support plate similar to that competitor’s, except for a few minor improvements.

Rather then use plastic, Zalman’s support plate is steel. It still flips over to accommodate Intel and AMD hole patterns, but uses threaded inserts and soft plastic insert holders to minimize motherboard contact and prevent annoying conflicts. Intel’s socket plate acts as a spacer to complete this low-impact design.

Zalman also puts a slightly different spin on the direct touch design concept by using four thin heat pipes instead of three fatter ones. Its base assembly is sanded completely flat, leaving only tiny sanding scratches to fill with thermal compound.

The top side of the Optima’s base is made in two parts, and sandwiches mounting brackets between them. Screws on the bottom pull down on the plate above.

Shoulders on the mounting screws eliminate the need for standoffs, allowing the CNPS10X Optima to be screwed directly to its support plate.

The Optima’s fan clips into place, with a little flexibility in height adjustment. Raising it allows additional DIMM clearance and lowering it allows more air to pass beneath the bottom fins towards the motherboard’s voltage regulator.

| Test System Configuration | |
|---|---|
| CPU | Intel Core i7-4770K (Haswell): 3.5 GHz Base Clock Rate, 8 MB Shared L3 Cache, LGA 1150, Overclocked to 4.50 GHz at 1.25 V (1.24 V Set) |
| Motherboard | Asus Z87-Pro Rev 1.02, BIOS 1007 (05/17/2013) |
| RAM | G.Skill F3-17600CL9D-8GBXLD (8 GB) at DDR3-1600 C9 Defaults |
| Graphics | Intel Integrated HD 4600 Graphics |
| Hard Drive | Samsung 840 Series MZ-7PD256, 256 GB SSD |
| Sound | Integrated HD Audio |
| Network | Integrated Gigabit Networking |
| Power | Corsair AX860i: ATX12V v2.3, EPS12V, 80 PLUS Platinum |
| Software | |
| OS | Microsoft Windows 8 Professional RTM x64 |
| Graphics | Intel 9.18.10.3071 |
| Chipset | Intel INF 9.4.0.1017 |
| Benchmark Configuration | |
| LinX 0.6.4 | Default benchmark at 500 repetitions |
| RealTemp 3.70 | Maximum Temperature, All Cores Averaged |
| Galaxy CM-140 SPL Meter | Tested at 1/4 m, corrected to 1 m (-12 db), dB(A) weighting |
Asus’ top-overclocking Z87-Pro lays the groundwork for thermal testing, but not without compromise: knowing that CPU throttling would prevent accurate thermal measurement, I decided to prevent that occurrence by reducing core voltage to 1.25V.
LinX 0.6.4 is the new application that generates the most taxing thermals using Intel's diminutive Haswell die. I also warned cooler manufacturers that we'd have to drop them from contention if the CPU reached 100° Celsius, since throttling would prevent accurate readings above that point. For our part, I kept the room temperature below 23° Celsius. I further prevented the case from affecting thermal readings by leaving the motherboard in open air, hanging the board vertically to replicate its position in a chassis.
Lacking any mechanical support for a hanging graphics card, I used integrated graphics during these tests.
The most noticeable feature of our temperature charts is the narrow range of approximately 12° between highest and lowest CPU core temperatures. Dismantled Core i7-4770s suggest that this is due to the interface material Intel uses. At best, this shows that huge improvements in cooling technology are needed to create relatively small drops in temperature.

The results are also the average of all four highest temperatures, and some cores run hotter than others.
Scythe’s Ashura is the hottest cooler to stay under the processor’s 100° limit at a room temperature of 23°. Zalman’s CNPS10X Optima failed the test at just over 21° room temperature, and hours of extra A/C were required to get the room cold enough to finish Argon AR01 and Night Hawk Frostbourne measurements.

We might have blamed Xigmatek’s white paint for the cooler’s inability to cope with a Haswell-based CPU at a mere 1.25 V, if not for the audible cues to fan speed. The slower speed likely corresponds to less airflow, though fin design is also a potential factor.
We saw a fairly wide range of fan speeds, and some coolers even had two fans. Yet, the difference in noise between the quietest and noisiest model is far less than the 10 dB(A) that would indicate doubled volume in the (logarithmic) decibel scale.

The Gamer Storm Assassin and Argon AR01 are roughly 50% noisier than Prolimatech’s as-delivered PRO-GNSS-BK. Since Prolimatech's heat sink requires additional fans though (fans aren't included with the heat sink), the noise we're reporting only represents this specific $125 combined configuration.
The relative scale for cooling-to-noise calculations refers to how each cooler relates to the average of all coolers in today’s test. Dividing the group average by each cooler’s result gives a higher percent score for lower temperatures. Dividing each cooler’s actual noise level by the group average produces a higher percent score for higher noise. Noise, however, is the divisor, and higher divisors produce lower dividends.
The results use a 100% baseline. Since nothing can be more than 100% efficient, we zero out the chart scale by subtracting 100%.

Besides being the quietest product, Prolimatech’s PRO-GNSS-BK configuration is also the third-coolest. That combination gives the firm a significant lead in our cooling-to-noise calculations. Hitting the middle of our cooling scale, a second-place finish in noise measurements gives the Noctua a second-place acoustic efficiency finish. Phanteks and Thermalright are the only two remaining companies to beat the class average.
We warned companies that any cooler that allowed our CPU to top 100° Celsius at 1.25 V would be disqualified from further contention, and found ourselves lucky that we were even able to get the room cold enough in July to finish testing. Of the coolers that survived our tests, Scythe’s Ashura barely qualified at a 98° maximum in a 23° room.

For many overclockers, that means Scythe’s top-value Ashura presents a worst-case cooling scenario, and that anything less powerful isn’t going to satisfy you if you're overclocking a Haswell-based processor. Noctua’s NH-U14S takes a distant second in value, and this $75 part is the cheapest (and hottest) cooler worthy of a full recommendation.

With a 29 decibel noise reading in our lab, Noctua’s NH-U14S climbs a little higher up the value chart when acoustics are considered. The top position of Scythe’s Ashura would qualify it for a value award, if not for the caveat that users must keep the inside of their case below 25° in order to make proper use of a modest 1.25 V overclock.
Here's the bombshell we figured out from today's testing: for overclocking, a quad-core Haswell-based processor at 22 nm requires more cooling than a six-core Sandy Bridge-E CPU at 32 nm, even though its lower power consumption produces less heat. The back-up for this is that two of the coolers from our Sandy Bridge-E cooling round-up re-appeared today with far worse apparent performance. Most overclockers blame Intel’s newer integrated heat spreader and transfer material for this discrepancy. These days, cheap paste replaces solder for connecting the CPU die to the spreader.
Cross-compatibility between LGA 1150, 1155, and 1156 sinks theoretically makes it possible for us to test dozens of heat sinks and fans. Unfortunately, most solutions are too small to cope with the heat issues an overclocked Haswell-based CPU suffers. Since Haswell has the smoothest thermal throttling implementation I’ve yet experienced, I set a simple rule that any cooler that hit its threshold temperature (100° Celsius) would be disqualified from final consideration. That guideline prevented the submission of many samples, and even knocked three of the coolers we tested out of contention. But it left a hole wide open for one cooler to slip through at a maximum core temperature of 75° over ambient. Nobody should be expected to keep the inside of their case cooler than 25°.
With a moderate price and moderate cooling capability, Scythe’s Ashura SCASR-1000 would have received our “Smart Buy” award if we didn’t need to warn you to keep your case below 25° internally. We'll save you the conversion. That's 77° Fahrenheit inside your case, just to run a Core i7-4770K at 1.25 V. And the company might still have won that award if we lowered our overclocking parameters. We don't think it'd be fair to hand out a prize, since we announced the settings we'd be using during the invite phase. However, if your overclocking expectations are lower than 4.5 GHz, we think you'll be pleased with the Ashura.
The top-performing configuration in our review, Prolimatech’s PRO-GNSS-BK with dual PRO-USV14 fans and PRO-USB-ARMG adapter clips would likewise be a contender for our highest-end “Elite” award, if not for its total build price. If I'm an enthusiast looking for the best of the best, which is what wins an Elite award from us, then I'm going to go with liquid cooling rather than spending a total of $125 on those parts, though we have to give Prolimatech credit for an elite collection of cooling components.
Noctua's NH-U14S isn't the strongest performer qualifying for our stamp of our approval, but it is the least-expensive option able to do what we need it to. Second place on our value charts behind the Ashura, which barely qualifies, the NH-U14S is effective enough to allow a 31° case temperature before our Core i7-4770K at 4.5 GHz started throttling under unusually stressful test loads. In other words, it allows us to get most of our intended performance most of the time.

If that sounds like a half-hearted justification, consider the field and consider our tepid response to Core i7-4770K in the first place. We aren't particularly enthused about Intel's latest effort, but Noctua's NH-U14S makes the best of a difficult situation.
