Best CPU Cooler Performance Q2-2010

Why do we overclock? It's really a very simple question, but one that has found new meaning over the years. It used to be that computer hardware enthusiasts had very few options when it came to choosing a processor, and building your own custom system was simply not possible. You looked for the best pre-built system, and compared Kilobytes of memory between choices. Those days are behind us, and now the computer hardware industry offers hundreds of processor, motherboard, memory, and peripheral hardware options. But the question still remains.

Its been more than a decade, but I still remember why I began overclocking: it was out of necessity, because my computer operated close to a modern day speed limit. This was back in the day when computers featured a 'Turbo' button, overclocking from 33 to 66MHz was a click away. It wasn't until around 1998 that I began visiting 'enthusiast' websites and found myself overclocking a pathetic Cyrix M-II 233MHz processor. My pursuit for speed would risk an entire Packard Bell computer system for the purpose of finishing reports faster. Back then, overclocking the CPU could push clock speeds past any production level. Today the market is different, and overclocking the processor could result in very little additional performance.

Now days I'm fortunate enough to afford top-end hardware, and so I no longer overclock out of need. With so many dual-, quad-, and hexa-core processors sold on the open market, it seems unnecessary to overclock for the sake of productivity. Overclocking has transformed itself from a tool to help people work faster, into a hobby for enthusiasts. There's a level of overclocking for every enthusiasts, from simple speed bumps to the record-breaking liquid nitrogen extreme projects. Overclocking is addictive, and before you know it the bug has you looking at hardware that might cost as much as a low-end computer system.

Enthusiast overclockers demand only the best performance from their computer hardware, which is why the aftermarket heatsink industry is thriving with fierce competition. Using an overclocked Intel Core i7 processor on the X58-Express platform, only the very best CPU coolers will endure. Benchmark Reviews tests the latest Intel LGA1366 heatsinks in this Best CPU Cooler Performance Q2-2010 article.

Computer hardware is an ever-evolving industry, and since Moore's law only applies to an exponentially growing transistor count then there should probably be another law for cooling products. In the very recent past there have been two major trends which have accelerated the performance potential of CPU cooler. That first development was the use of heat-pipes to directly contact with the CPU surface; which resulted in the Heat-pipe Direct Touch technology. The second development is by no mean a new concept, just new to our industry in specific. For many years now heatsinks have been full of right angles, but very recently companies have begun to recognize the need to disrupt smooth airflow and reduce the laminar skin effect which allows air to travel just above the solid surface. Some manufacturers have used at least one of these new concepts in their product design, and only a few are beginning to incorporate both. Benchmark Reviews will see how much this affects the overall performance as we test a large segment of enthusiast cooling products.

Before the Intel Core i7/X58 platform arrived, the Core 2 Duo and Core 2 Quad processors did their part to separate the cream of the crop from our large collection of LGA775 coolers. In a previous Best CPU Cooler Performance article, Benchmark Reviews retired the LGA775 platform from its testing duties and made room for the up-and-coming LGA1366 socket. It didn't take long to collect several CPU coolers designed for the Intel Core i7 CPU & X58 platform. It's a mistake to think that any LGA775 cooler can do just as well with the new LGA1366/Core i7 platform; primarily because the size and location of processor cores has changed.

Before we inspect each member of our new CPU cooler collection, let's establish that our tests consist of methods we have determined to be the best for our one singular purpose. Our methodology isn't written in stone, and could very likely be changed or modified as we receive justification (and feedback from the community). Our scope is limited to stand-alone products only, meaning those products which can be installed and operated without additional critical components needed or kit construction. This generally excludes most commercial liquid cooling systems, which may potentially offer better performance than the products we test for this article but require components to be assembled from various options and equipment. Suffice it to say, the vast majority of gamers and enthusiasts are using air-cooled solutions and therefore we target this review series towards them. We encourage hardware enthusiasts to utilize the equipment available to them, and select the cooling fan that best suits their needs. Just keep in mind that exceptional cooling performance must begin with the CPU cooler, and end with the cooling fan. It's the foundation of the unit that makes a difference, which is exactly what we're after in this article.

Thermally Conductive Elements

Manufacturers have made a small fortune off of confusion tactics and misinformation. Marketing departments often times neglect to refer back to solid science when making their bold claims, which is why we have assembled a complete list of thermally conductive elements in the reference chart below.

It's very well known that Silver, Copper, Gold, and Aluminum together comprise the top four most thermally conductive elements. However, without knowing the thermal conductance of these elements you might be fooled into thinking the performance was close. As it turns out, Silver and Copper both offer nearly twice the performance of Aluminum when transferring thermal energy such as heat. The reason Aluminum is used in so many applications is because it's the least expensive top-tier metal available. Most Thermal Interface Material and CPU coolers use several different elemental ingredients to work together, but after a careful inspection of the performance levels it comes as a surprise to me that some of the most popular products make use of such poor conductive elements.

Recipes usually call for only the finest ingredients, and the very same principle is true for overclocker and hardware enthusiast products. Thermal pastes are often times mixed from at least a dozen different components, while heatsink coolers may use only one or two different metals. Armed with the knowledge above, you might expect any silver-based product to be a clear-cut winner... but building a superior product by design is different than what you receive in execution. Production and material costs usually dictate how the product is designed and fabricated.

Keep these materials in mind as we take a look at the new products Benchmark Reviews has collected for this round-up article, beginning with our first contender...

Cooler Master V6 GT Heatsink

Aftermarket CPU coolers are the province of overclockers, and although performance is the primary consideration, other factors such as price, noise, and aesthetics can come into play as well. Cooler Master has a broad line of coolers ranging from stock-level replacement coolers to high-end enthusiast coolers; the V6GT represents the latest in their line of "V coolers" (which include the V8 and VTEC-enhanced V10) for the enthusiast market.

The cooler itself comprises 55 0.6mm-thick fins pierced by 6 heat pipes. Snap-on shrouds secure a 120x25mm fan on each side of the cooler, while a plastic plate on the top of the cooler contains an LED light strip whose color is controlled by pressing on the "Cooler Master" logo button on top of the unit. Both fans use four-pin PWM-controllable connectors, and Cooler Master supplies a "splice" cable that gangs both together so you can run both fans from your motherboard's CPU fan connector. A separate four-pin Molex connector provides power for the LED light strip at the top of the cooler. The fans are rated at 34-94 CFM per fan, which means the cooler can make use of over 180 CFM of air with both fans at full speed. The very observant might note that only the red connector of the splice cable provides the fan tachometer lead, which makes sense if you're plugging both fans into a single motherboard header.

Stripped of its fans and top plate, the Cooler Master V6GT seems to be a rather standard modern heat-pipe design. The fins are tilted at a slight 5 degree angle, which Cooler Master says improves cooling by allowing slightly more surface area in the same space and reducing turbulence in the airflow over the fins. The Cooler Master RR-V6GT-22PK-R1 CPU cooler includes the mounting hardware for Intel Socket 775/1156/1366, and AMD Socket AM2/AM2+/AM3. The Cooler Master V6GT is sold at NewEgg for $69.99 with fans. Benchmark Reviews has also published a full review of the Cooler Master V6GT CPU Cooler.

Features and Specification

• Model: RR-V6GT-22PK-R1
• CPU Sockets: Intel Socket LGA1366/1156/775 and AMD Socket AM3/AM2+/AM2
• Dimensions: 5.2 x 4.7 x 6.5 inch (131 x 120 x 165 mm)
• Heat Sink Materials: Copper base / Aluminum fins / 6 heatpipes
• Fin Thickness: 0.6 mm
• Fan Speed: 800- 2200 RPM (PWM)
• Fan Airflow: 34.02 - 93.74 CFM (per fan)
• Fan Air Pressure: 0.43 - 3.30 mmH2O (per fan)
• UPC Code: 884102008726

ProlimaTech Super Mega Heatsink

The ProlimaTech Super Mega clearly shares the Megahalems and Mega Shadow heatsink design, and presumably, the same cooling traits. Since critical details are important, it's worth noting that the ProlimaTech Super Mega heatsink, as with the previously released Megahalems and Mega Shadow CPU coolers, utilize a two-part construction for each fin plate. Of the 180 fin parts (44 inner and outer pieces per side and two top plate halves), several copper plates are stacked along the outside edges. 32 of the 88 outer fin plates are copper, and combined with nickel plating they increase the weight from 790g on the Megahalems to 945.3 grams on the Super Mega.

Each outer fin plate has been shaped to accept a wire fan frame, so that up to two 120mm or 140mm fans may be attached. While the fins are no wider than a 120mm fan, the attachments will secure larger fans to the heatsink. The Super Mega does not include a cooling fan, however two sets of 120/240 fan wire clips are enclosed with the accessory kit. In terms of physical heatsink differences, there have been only two: copper fin plates are positioned along the outside, and two polished nickel plates cover the top. The other change comes in the shape of a black spring-loaded screw. A pair of black 70LB 'extensive pressure' screws offer extreme surface compression between the processor and heatsink, which ProlimaTech warns against damage on every plastic bag. Standard compression silver spring-loaded screws are also included.

Based on the original ProlimaTech Megahalems model that is still available for $62 (without fans), look for the ProlimaTech Super Mega heatsink to go on sale at FrozenCPU with a list price of $69.99 or more. AMD users are still relegated into paying an extra $10 for the AM2/AM2+/AM3 mounting kit. Benchmark Reviews has also published a full article on the ProlimaTech Super Mega Heatsink CPU Cooler.

Features and Specification

Scythe Yasya SCYS-1000 Cooler

Scythe struck the perfect combination of performance and value with their Mugen 2 CPU cooler, which earned our Editor's Choice honors mention. Despite it's proven performance, there were critics of the large square design who wanted more excitement. Enter the Scythe Yasya heatsink, model SCYS-1000. This CPU cooler uses many of the same test-proven design features, and adds a whole new appearance inside the computer case.

The Scythe Yasya pairs staggered heat-pipe rods to a jagged aluminum fin array. An aluminum heatsink rides atop the nickel-plated copper base, and all six heat-pipe rods benefit from two ranges of cooling. Scythe includes one of their famous 120mm Slip Stream fans with the SCYS-1000 cooler kit, but there are wire retaining clasps for up to two 120mm fans attached to the front and back of the Yasya heatsink.

While the Scythe Yasya offers versatile mounting on both AMD and Intel processor sockets, the SCYS-1000 kit uses fragile plastic push-pin clips for Intel mounting while AMD clips make use of excellent clamping pressure. Unfortunately, Yasya lacks the bolt-through mounting system of the Mugen-2. On the other hand, Scythe utilizes a polished contact surface on Yasya, which works really well with thin/low viscosity pastes from our 80-way Thermal Interface Material Performance Test.

Features and Specification

• Name: Scythe Yasya
• Model Number: SCYS-1000
• Size (LxWxH): 130x108.5x159 mm / 5.12x4.27x6.26 in
• Weight: 29.91 oz (848 grams)
• Heatpipes: 6x 8mm Sintered
• Fan Placement: 2x 120mm Fan Support
• Application: Intel LGA775/1156/1366, AMD AM2/AM2+/AM3
• Clip System: Intel push-pin / AMD compression clip
• Mounting Pressure: High / Very High
• Base: Polished Nickel-plated Copper
• Price: $54.99

SilenX Effizio EFZ-120HA4

It's been a few years since SilenX products were tested at Benchmark Reviews, the last was their SilenX IXC-120HA2 heatsink which was identical in design to several other models. SilenX isn't well known for their iXtrema coolers, primarily because they reuse popular designs already on the market, but I must admit that the SilenX iXtrema Pro fans are the best 'silent' cooling fans ever tested. Building from the 3R-System IceAge Prima Boss-II design, they introduce the SilenX Effizio EFZ-120HA4. This SilenX heatsink devotes five staggered 8mm copper heat-pipe rods to form a 153mm-tall CPU-cooler unit, and notched fins allow for two 120mm fans to be attached to the unit.

SilenX includes 120x120x25mm Effizio series quiet fan, model EFZ-12025-HSF, with their Effizio EFZ-120HA4 heatsink. This 2000-RPM fan is advertised to offer 102 CFM at only 28 dBA, and features a black frame with white blades. The center hub on the EFZ-12025-HSF fan is standard size, while the SilenX iXtrema Pro fan series remains a personal favorite because of the reduced hub size. All of the SilenX iXtrema Pro fans are available from FrozenCPU.

The SilenX Effizio EFZ-120HA4 utilizes a familiar bolt-through mounting clip system, which means that installation requires access to the backside of the motherboard. Because of the bolt-through design, AMD systems must remove the plastic clip bracket surrounding the processor socket in order to accommodate the custom backplate. The bolt-through mounting system takes some effort to install, but allows high-pressure contact with the CPU on both AMD and Intel motherboards. The Effizio CPU cooler sells for $38.99 at NewEgg, which makes it an affordable after-market upgrade for enthusiasts and overclockers.

Features and Specification

• Name: SilenX Effizio
• Model Number: EFZ-120HA4
• Size (LxWxH): 131x105x153mm
• Weight: 1.84 LBS (836 Grams)
• Heatpipes: 5x 8mm Sintered
• Fan Placement: Supports 2x 120mm fans
• Application: Intel LGA775/1156/1366, AMD AM2/AM2+/AM3
• Clip System: Bolt-Through with Back-Plate
• Mounting Pressure: Very High
• Base Finish: Smooth Copper Heatpipes
• MSRP: $38.99

Thermalright Venomous-X RT Cooler

For as long as Benchmark Reviews has tested CPU coolers, the Thermalright Ultra-120 eXtreme (TRUE) has been a top contender. Although the TRUE leaves behind a very long legacy of revisions and changes, Thermalright has moved on with an improved design that borrows from established technology. The Thermalright Venomous-X is the fruit of those labors, and concentrates six nickel-plated copper 6mm heat-pipe rods into a staggered 'U' layout placed among dense aluminum "bent winglet" finsink plates.

There are two versions of the Thermalright Venomous-X: a standard version without any fans, and the $68 Thermalright Venomous-X RT which include one 120mm cooling fan and AMD mounting hardware.

Aside from the improved Venomous-X heatsink design, Thermalright has introduced a new high-pressure bolt-through mounting system they call 'Pressure Vault'. This bracket system is only sold with the Thermalright Venomous-X heatsink, but with enough feedback from consumers Thermalright may soon offer it separately for previous heatsink products. The Thermalright Venomous-X RT heatsink support the most current Intel LGA775/1156/1333 and AMD AM2/AM2+/AM3 sockets, while the standard Venomous-X version requires an additional $10 for the AMD mounting kit that extends compatibility to Athlon and Phenom processors.

Considerably better than previous TRUE heatsinks, the Thermalright Venomous-X receives a polished nickel finish on the contact base and removes the need for lapping. The extremely high-pressure mounting bracket system that's paired to the flat polished contact surface means that only a thin application of low viscosity thermal paste such as the included Chill-Factor TIM will offer the best results. Because the contact base uses a convex design, Thermalright suggests that enthusiasts avoid lapping the already-polished surface.

Features and Specification

• Name: Thermalright Venomous-X RT
• Model Number: CPU-TRI-74
• Size (LxWxH): 125x158x160mm
• Weight: 1.82 LBS (825 Grams)
• Heatpipes: 6x 6mm Sintered
• Fan Placement: Supports 2x 120mm
• Application: Intel LGA775/1156/1366 (AMD AM2/AM2+/AM3)
• Clip System: Bolt-Through with Back-Plate
• Mounting Pressure: Extremely High
• Base: Polished C1100 Nickel Plated Copper
• Price: $67.99

Zaward Vapor-120 ZCJ013 Cooler

Way back when Benchmark Reviews first began conducting CPU cooler tests, sometime around March 2007, there was an interesting little technology making its way to the consumer market: Heatpipe Direct Touch. Zaward was first to introduce a retail HDT product named ZikaRay ZIKA-01 around February 2007. A few months later Xigmatek used the same HDT concept to design several exposed heatpipe CPU coolers, and bring the enthusiast heatsink market to a whole new level. It was (and still remains) unclear who actually invented Heatpipe Direct Touch technology, although I've been told a company named Golden Sun News Techniques Corporation in Taiwan holds the patent.

Zaward has remained connected to the enthusiast cooling industry for many years, even despite some lukewarm yet innovative designs (see Zaward Gyre ZCJ010). They return with the Zaward Vapor-120 ZCJ013, a heatsink that provides all of the basic features needed for an extraordinary CPU cooler.

The Zaward Vapor-120 heatsink appears to look very similar to the popular Xigmatek HDT-S1283, but that's probably because you weren't aware that the fairly obscure Zaward VIVO PCJ004 cooler that came out at the same time. In many ways, this is Zaward's improved version of the VIVO, minus plastic cladding. One stand-out feature that separates the Zaward Vapor-120 from previous products is the use of dimpled aluminum fins, last seen on the award-winning OCZ Vendetta-2.

One-piece aluminum fins are pressed onto three 8mm copper heat-pipe rods to create the Zaward Vapor-120 ZCJ013 heatsink. Zaward includes one of their famous 'Golf' fans, which features dimpled blades and Duro long-life bearings, with their Vapor-120. The heatsink also includes mounting hardware for both AMD and Intel processor sockets, allowing for diverse motherboard installation.

Selling for $44.99, it's difficult to imagine that the Vapor-120 adds more cooling performance for the price when nearly identical clones sell for considerably less. Benchmark Reviews will soon see how well the Zaward Vapor-120 performs against the competition.

Features and Specification

• Name: Zaward Vapor-120
• Model Number: ZCJ013
• Size (LxWxH): 120x50x160mm
• Weight: 1.51 LBS (684 Grams)
• Heatpipes: 3x 8mm Sintered
• Fan Placement: Supports 2x 120mm
• Application: Intel LGA775/1156/1366, AMD AM2/AM2+/AM3/754/939/940
• Clip System: Bolt-Through with Back-Plate
• Mounting Pressure: Very high
• Base: Smooth Copper Heatpipes
• Price: $44.99

Contact Surface Preparation

Processor and CPU cooler surfaces are not perfectly smooth and flat surfaces, and although some surfaces appear polished to the naked eye, under a microscope the imperfections become clearly visible. As a result, when two objects are pressed together, contact is only made between a finite number of points separated by relatively large gaps. Since the actual contact area is reduced by these gaps, they create additional resistance for the transfer of thermal energy (heat). The gasses/fluids filling these gaps may largely influence the total heat flow across the surface, and then have an adverse affect on cooling performance as a result.

Surface Finish Impact

CPU coolers primarily depend on two heat transfer methods: conduction and convection. This being the case, we'll concentrate our attention towards the topic of conduction as it relates to the mating surfaces between a heat source (the processor) and cooler. Because of their density, metals are the best conductors of thermal energy. As density decreases so does conduction, which relegates fluids to be naturally less conductive. So ideally the less fluid between metals, the better heat will transfer between them. Even less conductive than fluid is air, which then also means that you want even less of this between surfaces than fluid. Ultimately, the perfectly flat and well-polished surface is going to be preferred over the rougher and less even surface which required more TIM (fluid) to fill the gaps.

This is important to keep in mind, as the mounting surface of your average processor is relatively flat and smooth but not perfect. Even more important is the surface of your particular CPU cooler, which might range from a polished mirror finish to the absurdly rough or the more complex (such as Heat-Pipe Direct Touch). Surfaces with a mirror finish can always be shined up a little brighter, and rough surfaces can be wet-sanded (lapped) down smooth and later polished, but Heat-pipe Direct Touch coolers require some extra attention.

To sum up this topic of surface finish and its impact on cooling, science teaches us that a smooth flat mating surface is the most ideal for CPU coolers. It is critically important to remove the presence of air from between the surfaces, and that using only enough Thermal Interface Material to fill-in the rough surface pits is going to provide the best results. In a perfect environment, your processor would mate together with the cooler and compress metal on metal with no thermal paste at all; but we don't live in perfect world and current manufacturing technology cannot provide for this ideal environment.

Mounting Pressure

Probably one of the most overlooked and disregarded factors involved with properly mounting the cooler onto any processor is the amount of contact pressure applied between the mating surfaces. Compression will often times reduce the amount of thermal compound needed between the cooler and processor, and allow a much larger metal to metal contact area which is more efficient than having fluid weaken the thermal conductance. The greater the contact pressure between elements, the better it will conduct thermal (heat) energy.

Unfortunately, it is often times not possible to get optimal pressure onto the CPU simply because of poor mounting designs used by the cooler manufacturers. Most enthusiasts shriek at the thought of using the push-pin style clips found on Intel's stock LGA775 thermal cooling solution. Although this mounting system is acceptable, there is still plenty of room for improvement.

Generally speaking, you do not want an excessive amount of pressure onto the processor as damage may result. In some cases, such as Heat-pipe Direct Touch technology, the exposed copper rod has been pressed into the metal mounting base and then leveled flat by a grinder. Because of the copper rod walls are made considerably thinner by this process, using a bolt-through mounting system could actually cause heat-pipe rod warping. Improper installation not withstanding, it is more ideal to have a very strong mounting system such as those which use a back plate behind the motherboard and a spring-loaded fastening system for tightening. The Noctua NH-U12P is an excellent example of such a design.

In all of the tests which follow, it is important to note that our experiments focus on the spread pattern of thermal paste under acceptable pressure thresholds using either a push-pin style mounting system or spring-loaded clip system. In most situations your results will be different than our own, since higher compression would result in a larger spread pattern and less thermal paste used. The lesson learned here is that high compression between the two contact surfaces is better, so long as the elements can handle the added pressure without damaging the components.

Thermal Paste Application

The entire reason for using Thermal Interface Material is to compensate for flaws in the surface and a lack of high-pressure contact between heat source and cooler, so the sections above are more critical to good performance than the application of TIM itself. This section offers a condensed version of our Best Thermal Paste Application Methods article.

After publishing our Thermal Interface Material articles, many enthusiasts argued that by spreading out the TIM with a latex glove (or finger cover) was not the best way to distribute the interface material. Most answers from both the professional reviewer industry as well as enthusiast community claim that you should use a single drop "about the size of a pea". Well, we tried that advice, and it turns out that maybe the community isn't as keen as they thought. The example image below is of a few frozen peas beside a small BB size drop of OCZ Freeze TIM. The image beside it is of the same cooler two hours later after we completed testing. If there was ever any real advice that applies to every situation, it would be that thermal paste isn't meant to separate the two surfaces but rather fill the microscopic pits where metal to metal contact isn't possible.

After discussing this topic with real industry experts who are much more informed of the process, they offered some specific advice that didn't appear to be a "one size fits all" answer:

1. CPU Cooling products which operate below the ambient room temperature (some Peltier and Thermo-electric coolers for example) should not use silicon-based materials because condensation may occur and accelerate compound separation.
2. All "white" style TIM's exhibit compound breakdown over time due to their thin viscosity and ceramic base (usually beryllium oxide, aluminum nitride and oxide, zinc oxide, and silicon dioxide). These interface materials should not be used from older "stale" stock without first mixing the material very well.
3. Thicker carbon and metal-based (usually aluminum-oxide) TIM's may benefit from several thermal cycles to establish a "cure" period which allows expanding and contracting surfaces to smooth out any inconsistencies and further level the material.

The more we researched this subject, the more we discovered that because there are so many different cooling solutions on the market it becomes impossible to give generalized advice to specific situations. Despite this, there is one single principle that holds true in every condition: Under perfect conditions the contact surfaces between the processor and cooler would be perfectly flat and not contain any microscopic pits, which would allow direct contact of metal on metal without any need for Thermal Interface Material. But since we don't have perfectly flat surfaces, Thermal Material must fill the tiny imperfections. Still, there's one rule to recognize: less is more.

Heatpipe Directional Orientation

Heat-pipe technology uses several methods to wick the cooling liquid away from the cold condensing end and return back towards the heated evaporative end. Sintered heatpipe rods help overcome Earth's gravitational pull and can return most fluid to its source, but the directional orientation of heatpipe rods can make a significant difference to overall cooling performance. For the purpose of this article, all CPU-coolers have been orientated so that heatpipes span from front-to-rear with fans exhausting upward and not top-to-bottom with fans blowing towards the rear of the computer case. This removes much of the gravitational climb necessary for heatpipe fluid working to return to the heatsink base. In one specific example, the horizontally-mounted ProlimaTech Megahalems heatsink cooled to a temperature 3° better than when it was positioned vertically. While this difference may not be considered much to some people, hardcore enthusiasts will want to use every technique possible to reach the highest overclock possible.

Heatsink Test Methodology

Benchmark Reviews is obsessed with testing CPU coolers, as our Cooling Section has demonstrated over the past few years. We've solicited suggestions from the enthusiast community, and received guidance from some of the most technical overclockers on the planet. As a result, our testing methodology has changed with every new edition of our Best CPU Cooler Performance series. Because of this, each article is really its own stand-alone product, and cannot be fairly compared to the others. This particular article is a perfect example of that principle, since we're using a fresh methodology. Benchmark Reviews continues to test CPU coolers using the stock included fan (whenever applicable), and then replace it with a high-output fan for re-testing.

Manufacturers are not expected to enjoy this sort of comparison, since we level the playing field for all heatsinks by replacing their included fan with a common unit which is then used for every CPU cooler tested. Many manufacturers include fans with their heatsink products, but most 'stock' fans are high-RPM units that offer great airflow at the expense of obnoxiously loud noise levels. By using the same model of cooling fan throughout our heatsink tests, we can assure our results are comparable across the board. This is one of the more significant changes we have made to our test methodology, since many of the benchmark tests we have conducted in the past have compared the total package. Ultimately we're more interested in the discovering the best possible heatsink, and we believe that you'll feel the same way.

Yate Loon S12SH-12 Cooling Fan (Special)

Testing was conducted in a loosely scientific manner. Ambient room temperature levels were maintained within one degree of fluctuation, and measured at static points beside the test equipment with a calibrated digital thermometer. Manufacturer-supplied thermal paste was not used in these tests, and a common Thermal Interface Material of our choosing (listed in the support equipment section below) was utilized instead. The processor received the same amount of thermal paste in every test, which covered the ICH with a thin nearly-transparent layer. The heatsink being tested was then laid down flat onto the CPU, and compressed to the motherboard using the supplied retaining mechanism. If the mounting mechanism used only two point of force, they were tightened in alternation; standard clip-style mounting with four securing points were compressed using the cross-over method. Once installed, the system was tested for a baseline reading prior to testing.

At the start of each test, the ambient room temperature was measured to track any fluctuation throughout the testing period. Lavalys EVEREST Ultimate Edition was utilized to create 100% CPU-core loads and measure each individual processor core temperatures. It's important to note that software-based temperature reading reflects the thermal output as reported from the CPU to the BIOS. For this reason, it is critically important (for us) to use the exact same software and BIOS versions throughout the entire test cycle, or the results will be incomparable. All of the units compared in our results were tested on the same motherboard using the same BIOS and software, with only the CPU-cooler product changing in each test. These readings are neither absolute nor calibrated, since every BIOS is programmed differently. Nevertheless, all results are still comparable and relative to each products in our test bed (see The Accuracy Myth section below).

Since our test processor report core temperatures as a whole number and not in fractions, all test results utilize EVEREST to report averages (within the statistics panel), which gives us more precise readings. To further compensate for this, our tests were conducted several times after complete power down thermal cycles. Conversely, the ambient room temperature levels were all recorded and accurate to one-tenth of a degree Celsius at the time of data collection.

When each cooler is tested, Benchmark Reviews makes certain to keep the hardware settings identical across the test platform. This enables us to clearly compare the performance of each product under identical conditions. While the ambient room temperature did fluctuate between 24.9~25.9°C during testing, the thermal delta would not change enough to impact our test results. Benchmark Reviews reports the thermal difference in test result charts. For the purpose of this article, thermal difference (not the same as thermal delta) is calculated by subtracting the ambient room temperature from the recorded CPU temperature.

Intel Test System

• Processor: Intel Core i7-920 BX80601920 2.66 GHz (overclocked to 3.6 GHz @ 1.375V)
• Motherboard: ASUS P6T Deluxe V2 (Intel X58-Express Chipset)

Support Equipment

• Lavalys EVEREST Ultimate Edition v5.50
• Yate Loon 120x120x25mm fan, model D12SH-12 (88 CFM Advertised @ 40 dBA) 12V/0.30A
Scythe Kaze-Jyuni 'Slip Stream' 120x120x25mm fan, model SY1225SL12SH (110.31 CFM Advertised @ 37.0 dBA) 12V/0.53A

All of the tests in this article have been conducted using vertical motherboard orientation, positioned upright in a sealed traditional tower computer case. Heatsinks are positioned so that heatpipe rods span horizonally, and described in our Heatpipe Directional Orientation from the previous section.

At the start of our test period, the test system is powered on and EVEREST system stability tests are started with Stress CPU and Stress FPU options selected. For a minimum of thirty minutes (one hour) EVEREST loads each CPU core to 100% usage, which drives the temperature to its highest point. Finally, once temperatures have sustained a plateau, the ending ambient room temperature and individual CPU core levels are recorded thus completing the first benchmark segment.

The second test segment involves removing the stock cooling fan (while the system is still under load) and replacing it with a high-output 120 mm Yate Loon D12SH-12 cooling fan. The system is given thirty additional minutes with EVEREST loading the CPU cores before final temperature readings are taken and recorded.

The Accuracy Myth

All modern processors incorporate an internal thermal diode that can be read by the motherboards' BIOS. While this diode and the motherboard are not calibrated and therefore may not display the actual true temperature, the degree of accuracy is constant. This means that if the diode reports 40°C when it's actually 43°C, then it will also report 60°C when it's truly 63°C. Since the design goal of any thermal solution is to keep the CPU core within allowable temperatures, a processor's internal diode is the most valid means of comparison between different heatsinks, or thermal compounds. The diode and motherboard may be incorrect by a small margin in relation to an actual calibrated temperature sensor, but they will be consistent in their margin of error every time.

Heatsink Performance: Stock Cooling Fan

Benchmark Reviews tries to cover every angle, but sometimes it's just not possible given our time constraints. Initial articles from our 'Best CPU Cooler Performance' series originally focused on the Intel Core 2 Duo/Quad LGA775 socket, and while the results are relevant to users owning that series of processor the new Core i7 platform is completely different. To the inexperienced enthusiast, a top-performing LGA775 cooler might be (mistakenly) considered worthy for cooling a new LGA1366 Core i7 project. This would be a grave error, because not only are the two processors different in overall die size, but they also place the processor cores in different locations. Simply stated: what worked fine on a Core 2 platform may not work very well at all with Core-i7.

We previously tested heatsinks using the Intel Core i7-980X Extreme Edition six-core Gulftown processor, overclocked to 4.0GHz. Although we had good intentions, the lack of vCore headroom left our thermal tests somewhat flat. In this article David Ramsey uses his over-volted Intel Core i7-920 to produce test results on CPU coolers using stock manufacturer-included cooling fans. Whenever a cooler did not include a fan, the silent-yet-powerful Scythe Kaze-Jyuni SY1225SL12SH was used. Manufacturer-supplied stock cooling fans usually offer either extremely high airflow or incredibly low noise, so there's a lot riding on what's packaged with the kit. Sure, there's added importance on the cooler's design and construction, but at the stock level these factors really don't carry tremendous weight.

Benchmark Reviews has tested several new products against some proven top-performers from previous tests in this section, all using stock fans on the Intel LGA1366 socket. The average temperature difference (core temp minus ambient temp) is noted beside each heatsink:

* No manufacturer supplied fan. Tests use Scythe Kaze-Jyuni 'Slip Stream' SY1225SL12SH.
** Manufacturer supplied fan require speed controller. Fan speed set to high.

Best CPU Cooler: Stock Fan Performance

Thanks to a pair of powerful 120mm cooling fans, the Cooler Master V6-GT heatsink provides the best out-of-box performance and leads the pack with 42.4°C over the ambient room temperature. Equipped with only a single Scythe Kaze-Jyuni 'Slip Stream' silent cooling fan, the ProlimaTech Megahalems (43.3°C), Super Mega, and Thermalright Venomous-X (43.8°C) all trail behind the V6-GT.

Scythe's Mugen 2 (45.4°C) uses the Scythe Kaze-Jyuni fan by default, which competes directly with specially-controlled fan on their Yasya cooler (45.5°C). The Zalman CNPS10X Performa (45.6°C) performs nearly the same as Scythe's monster heatsinks, while the Zaward Vapor-120 (45.7°C) also keeps up well. Previous tests indicate that this performance segment is also home to the $70 Cogage Arrow, and $40 Cogage TRUE Spirit.

The third tier of cooling performance begins with the Xigmatek Balder SD1283 (47.1°C), which finishes ahead of the Scythe-equipped Xigmatek Thor's Hammer S126384 (48.2°C). The Titan Finrir's stock fan earns 48.7°C, which edges out the silent-running SilenX Effizio cooler (49.5°C).

Taken as a whole, every single heatsink tested here performed very well with an already-overclocked Intel Core i7-920 processor running at 1.375 volts vCore. If you want to see how all of these coolers performed with a high-volume Yate Loon cooling fan attached, please continue into the next section...

Heatsink Performance: High-Output Fan

Overclockers are known for being particular to their equipment, which is why Benchmark Reviews changes our format with each new project. Although it's impossible to nail-down which cooling fan is the overwhelming choice for overclocker projects, most enthusiasts would agree that fans with the best static pressure and highest airflow are the most appropriate. Because of size and design constraints in most of these products, a 120x120x25mm fan is as large as we can go with our collection of CPU coolers. This section uses the 'special' high-output Yate Loon D12SH-12 cooling fan on each product tested. Most D12SH-12 cooling fans force 88 CFM of air at a moderately noisy 40 dBA, but the clear acrylic version we use (see Heatsink Test Methodology section for image) performs better than most 120x120x38mm fans we've tested.

Benchmark Reviews tests this heatsink collection with the same high-output fan for each cooler, using an overclocked and over-volted Core i7-920 with 1.375V vCore. While some enthusiasts may dare to trespass beyond this voltage, Benchmark Reviews needed our test system to remain functional long enough to complete testing on all products under several different conditions. Please keep in mind that every product must complete testing on the exact same motherboard and processor for our results to be comparable, and if one of these fail all the testing must be redone completely.

All of the top performing CPU coolers have a few things in common: bolt-through mounting clip systems that create impressive contact pressure. Although some mounting systems are better designed than others, The mounting system on the ProlimaTech Megahalems and Armageddon heatsinks use a bolt-through system with slotted alloy plates to ensure a perfectly centered cooler, which was a good bit better than the Xigmatek Crossbow kits we use on compatible coolers. The new 70LB screws that come with the ProlimaTech Super Mega, along with the Thermalright Venomous-X heatsink 'Pressure Vault' mounting kit, create a dangerous amount of contact pressure on the processor. Although we were able to tighten these coolers all the way down without incident, our readers should take caution.

Thermalright's Ultra-120 eXtreme, Cogage TRUE Spirit, and Cogage Arrow all use a similar bolt-through kit that creates substantial contact pressure. At least half of our CPU cooler collection have very flat mirror-finished contact surfaces, whereas the other half use Heat-pipe Direct Touch (HDT) technology. Every single one of these coolers have either large-gauge heat-pipes, or several pairs of heat-pipe rods integrated into the base. In my opinion nearly every single product on this chart is an outstanding aftermarket cooler, but only a select few can be considered the very best!

Benchmark Reviews reveals the results of our Intel LGA1366 CPU-cooler performance tests using high-output cooling fans in the chart below:

Very recently another staff member and I each tested the ProlimaTech Super Mega directly against the older Megahalems model. In that review, the Super Mega trailed behind the Megahalems in both independent tests, just as it does here again. When a heatsink costs $62 it had better be really good... and thankfully the ProlimaTech Megahalems really is. Cooling to a temperature of only 39.3°C over ambient, the Megahalems keeps the Super Mega (39.5°C) and $68 Thermalright Venomous-X RT (39.8°C) heatsinks trailing right behind. All three of these heatsinks come with smooth/polished base, and a high-pressure bolt-through mounting system.

Validating that our Benchmark Reviews Editors Choice Award was hard-earned, the Scythe Mugen-2 produces an impressive 41.8°C over ambient while costing only $35. If you're not after any overclocking world-records, and you don't mind the giant size and installation hassle, this could easily be the best value of the bunch. For reference, the Cogage Arrow delivers similar performance for twice the size and cost. Distanced a noticeable margin behind, the Xigmatek Balder SD1283 (43.1°C), SilenX Effizio EFZ-120HA4 (43.4°C), Scythe Yasya (43.5°C), Zalman CNPS10X-Perform (43.7°C), and Xigmatek Thor's Hammer S126384 (43.8°C) all occupy a slice of the pie roughly 1/2-degree wide.

Other coolers are worth mentioning here, even though they weren't tested/charted for this article. The SilenX Effizio is a clone of the 3R-System IceAge Prima Boss-II, so it could be argued that they might perform the same as well. Likewise for the massive Tuniq Tower-120 Extreme, which has tested to produce similar performance despite the $65 price tag.

Taking two stock fans off and replacing them with one Yate Loon fan caused the Cooler Master V6 GT to lose its edge and produce 44.4°C; two degrees more than stock. The $44.99 Zaward Vapor-120 heatsink, with it's very similar design to the Xigmatek HDT-S1283 and $25 Kingwin RVT-12025 clone, produced a respectable 44.5°C. Titan's FINRIR cooler produced 45.6°C, and matches the Coolink Corator-DS, Noctua NH-U12P, and Thermaltake Contac-29.

CPU Cooler Final Thoughts

There is one minor drawback to using the Core i7 or Phenom II processors which affects overclockers: the difference in CPU cooler mounting dimensions. Many overclockers and enthusiasts have grown to cherish their favorite cooler, and trust them to cool the hottest system they can build. The problem is that now many manufacturers are offering free adapter kits, or include an adapter with their current model coolers, which leads to bigger problems because of processor differences. For all of our LGA1366 test products, we used the Xigmatek ACK-I7361 or ACK-I7363 CrossBow bolt-through mounting kits whenever possible.

Heatsinks made for the old LGA775 platform are designed for use with a Core 2 (Duo or Quad) or Pentium 4 and D processor with an integrated heat-spreader measuring 28.5 x 28.5mm (812.25mm total area), but the LGA1366 socket requires a much larger 32 x 35mm (1120mm total area) footprint to accommodate the extra 591 'pins'. Then there's the LGA1156 socket, which measure 30mm square for 900mm of area. If you use an LGA775 or LGA1156 cooler on a LGA1366 socket, your missing out on up to 38% (307.75mm) of the contact surface. Additionally, the cores are located in slightly difference locations; the Core 2 Quad is slightly spaced away from the center, while the Core i7 is concentrated there.

The Phenom II processor series from AMD offer a very large 37.31 x 37.31mm (1392.04mm total area) integrated heat-spreader surface, which is the largest processor surface I can recall since the original Intel Pentium (I) days. Compared to Intel's Core 2 Duo and Quad processors which measure 28.5 x 28.5mm, the Phenom II offers over 71% more contact surface area. If you compare the latest Intel Core i7 processors which measure 32 x 35mm, then the Phenom II series offers 24% more contact surface area. For overclockers, this will mean a much larger area to cool, but also much more manageable temperatures.

There are a lot of different products out there, and believe it or not we exclude a few from each article because they don't stack up well at all. So this is why you may not see some of the coolers other sites have tested in our results. Because of space and time limitations it's just simply not feasible to review them all, but it's certainly worth mentioning which products should be avoided. So I began to carefully think about it and nearly constructed a real-time chart which places products into different levels of performance. That's when I realized that performance is relative, too, and what performs well today might be considered low-end only a year from now. Perhaps the best method for testing is to use a synthetic system to generate the same exact load for each and every test conducted. This would stand the test of time much better than any computer system or processor platform would, because temperature is a static measurement, but it wouldn't take into account the differences seen between processor model architecture.

The synthetic test unit might generate 250W of thermal energy, but every CPU series has a different layout and might not mate perfectly to a particular cooler. This brings me to my final point: there's a cooler for every processor and purpose. The ordinary casual computer user is fine with the included thermal cooling solution that comes with the retail processor kit. Systems built with a Core 2 Duo processor and three-piped HDT cooler (like the HDT-S1283 or Vendetta 2) will not be cooled the same as a Core 2 Quad processor because of where the cores align with the heat-pipes. Likewise, coolers built around the Core 2 LGA775 design may not perform well at all with the Core i7 or Phenom II platforms. This is why the research is so critical, and understanding the product is important.

Best CPU Cooler Conclusion

This quarters' Best CPU Cooler Performance article wasn't nearly as large as the previous edition in our series, primarily because there have been very few new heatsink products that have made it to market before July 2010. Despite our best efforts, not every CPU cooler is discovered and requested prior to testing. There are so many products that deserve attention, even if they don't top our results, so don't think for a minute we've intentionally left someone out. In order for this series to hit the target audience with the most relevant product coverage, Benchmark Reviews needs your feedback! Let us know what to test, and where to find it!

Between the last Best CPU Cooler Performance project that covered Intel LGA1366 and AMD AM3 sockets, and the final LGA775 article (Best CPU Cooler Performance LGA775 - Q4 2008), I've learned that processor architecture can have a huge impact on heatsink performance. I'm not referring to speed or voltages here, because those factors are a given when it comes to cooling. What I'm referring to is how the 45nm Intel Bloomfield Core-i7 is going to have a 'heat signature' area that differs slightly from 32nm Gulftown. In fact, Gulftown's 248mm² die package is closer to a Lynnfield LGA1156 Core-i7 CPU. Those heatsinks with a larger contact surface (and heatpipe base) will best serve 45nm AMD Phenom-II processors with a 258mm² die or 45nm Intel Core-i7 quad-core 263mm² Bloomfield CPU's. Essentially, it's important to research the cooler's physical information in addition to performance results when you're shopping for a CPU cooler. It's not a one-size-fits-all heatsink market, and the biggest cooler doesn't always provide the best performance. With these consideration in mind, I will offer several different product suggestions based on these test results and my past experience.

IMPORTANT: Although the recommendations mentioned in this conclusion are made to be as objective as possible, please be advised that every author perceives these factors differently at various points in time. While we each do our best to ensure that all aspects of the product are considered, there are often times unforeseen market conditions and manufacturer changes which occur after publication that could render our rating obsolete. Please do not base any purchase solely on our conclusion, as it represents our product rating specifically for the product tested which may differ from future versions. Because manufacturers and retailers often change product pricing based on media favoritism, we urge you to consider all factors when making your purchase.

High-Performance Overclocker Heatsinks

These heatsinks are suggested based on quality, value, and cooling potential:

1. ProlimaTech Megahalems: Using the best mounting system we've ever tested this heatsink delivers extraordinary contact surface pressure between the processor and polished base. The results produce the best cooling performance we've seen. As of July 2010 the ProlimaTech Megahalems was available at FrozenCPU for $61.99, or from NewEgg for $62.00. AMD users will also want the AM2/AM2+/AM3 mounting kit from FrozenCPU for an extra $10. Adding two high-output cooling fans will make Megahalems unstoppable.
2. Thermalright Venomous-X RT: The new 'Pressure Vault' mounting system offers incredible contact pressure, and pairs a polished contact surface to densely packed heatsink that supports two 120mm cooling fans. The Venomous-X RT kit costs $68, and includes AMD AM2/AM2+/AM3 mounting hardware and one 120mm cooling fan. As a standalone CPU cooler, Venomous-X delivers on its years of past design experience.
3. Scythe Mugen-2 SCMG-2100: Trailing right behind the two leaders is the $35 Mugen-2 cooler, which already includes AMD mounting hardware and a premium Scythe Kaze-Jyuni Slip-Stream fan... all for only half the cost of the the other two options. The SCMG-2100 model has already received our Editor's Choice Award honorable mention pertaining to value, and it consistently finishes at the very top. The Scythe Mugen-2 Revision B model SCMG-2100 heatsink is identical to the first version, model SCMG-2000, but SCMG-2100 includes a newly developed F.M.S.B. (Flip Mount Super Back-Plate) for more convenient mounting onto the motherboard and the thermal paste has been replaced by SCYTE-1000.
4. Cogage Arrow CPU-TRI-72: This dual-tower giant comes equipped with on 120mm cooling fan and Intel mounting hardware. Although our tests of the Cogage Arrow have never placed its performance above the previously listed heatsinks, the potential is certainly there. Priced at $70 before an optional AMD AM2/AM2+/AM3 mounting system for $10, the Cogage Arrow could tame your overclocked beast... presuming the cage is large enough.
5. Xigmatek Balder SD1283: Based on the original HDT-S1283 design, Balder offers some subtle improvements that help it maintain top-rated cooling performance in our tests. While the Balder kit includes a bolt-through mounting kit and costs $45, the original Xigmatek HDT-S1283 model uses push-pin clips and sells for $35. If you like the HDT-S1283 design but don't have much money, the Kingwin RVT-12025 is an identical clone that sells for only $22.

Enthusiast Heatsink Considerations

If you're not planning to increase vCore voltage to your processor, here are some additional recommendations that could fit your build:

• Cogage TRUE-Spirit: Priced at $40, this heatsink takes the Thermalright Ultra-120 Extreme (TRUE) design essence and fits it into a smaller more affordable CPU cooler. Our tests of the Cogage TRUE Spirit has always delivered impressive performance, and although only Intel LGA1156/1366 sockets are supported, an optional AMD AM2/AM2+/AM3 mounting system is available for $10.
• Thermaltake Contac-29 CL-P0568: Hardcore overclockers demand only the best cooling performance, and the Thermaltake Contac-29 generally trails the top leaders despite its virtually identical design to the Xigmatek HDT-S1283 series. NewEgg no longer stocks this item, but FrozenCPU still sells the multi-socket CL-P0568 kit for $40.
• GELID Tranquillo CC-TRANQ-01-A: GELID has declined to send us a sample for our round-up comparisons, explaining that their product is designed for low-noise application and not top-end overclockers. We disagree. Paired with a high-output cooling fan, the Tranquillo heatsink could offer an affordable CPU cooler for only $40.
• Zaward Vapor-120 ZCJ013: A sturdy bolt-through mounting system combined with dimpled heatsink fins and 'Golf' fan blades keep performance up and noise down. Selling for $45 this could offer ample cooling protection to moderatly overclocked processors, plus it's compatible with every motherboard socket currently in existence.
• Scythe Ninja-3 SCNJ-3000: Although the results of our Ninja-3 tests have yet to be published, this heatsink embodies the test-proven design of the Mugen-2 and other heatsinks. Scythe products have already earned many awards from us, and for $50 this not-so-subtle CPU cooler could be the next in line.

Benchmark Reviews encourages you to leave comments (below), or ask questions and join the discussion in our Forum.

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