Prolimatech Megahalems Heatsink Review

Throughout all of 2008, I made it my mission to test every high-performance CPU cooler that Benchmark Reviews received. 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 our 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, which led to the Best CPU Cooler Performance LGA1366 - Q1 2009 round-up article focusing on a wide selection of performance-cooling products for overclockers. 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.

With nearly twenty different LGA1366 kits tested in our Best CPU Cooler Performance LGA1366 - Q1 2009 article, one particular product stood out as an up-and-coming favorite. The Prolimatech Megahalems is a CPU cooler build from scratch using over twenty years of industry design experience and engineering. While the Prolimatech name is new to most enthusiasts, the look is not. Based on the successful Thermalright Ultra-120 eXtreme CPU cooler, Magahalems incorporates all-new engineering to correct weaknesses in the aging TRUE design. The result is astonishing, and the thermal cooling performance Benchmark Reviews received in testing was proof evident that you don't need HDT technology to be the best.

When it comes down to it, those consumers shopping for aftermarket cooling products only want one thing out of them: the very best cooling performance their money can buy. It makes perfect sense, too. Since so many products flood the market, it all comes down to price and performance. Based on this principle, Benchmark Reviews searches out the latest CPU coolers and tests them under real-world overclocked conditions. Want to know which cooling products stand-out? This quarterly update to our Best CPU Cooler Performance series will separate the good from the bad... but we also find those products that are truly exceptional and deserving of your hardware projects.

Benchmark Reviews strives to offer the overclocker and hardware enthusiast community solid evidence reflecting the true performance of computer products through rigorous testing and evaluation. I personally understand that many of the readers who visit Benchmark Reviews have been involved with other community websites for several years, and therefore take our test results personally. So now that our test process has been reworked, we have collected the most complete source of benchmark results possible and gathered in a controlled environment.

Computer hardware is an ever-evolving industry, and since Moores law only applies to an exponentially growing transistor count then there should probably be another law for cooling. 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.

About Prolimatech Inc

Prolimatech, founded in 2008 is headquartered in Taiwan, led by a team of dedicated experts with 22 years of accumulated experience in the field of computer thermal solutions. Prolimatech stands for Professionalism exceeding beyond all Limits. We are here to challenge any limits that stand in our way to achieve what was thought to be impossible. Prolimatech incorporates integration of the aerospace resource-saving technology and advanced heat conduction technology to create the best heat absorption and dissipation solutions while pertaining to the science of aesthetics. Our never-ending quest is to satisfy every computer overclocker's and every enthusiast's needs for high quality and performance oriented thermal solutions for their high-end computer components.

Prolimatech Megahalems CPU Cooler

What happens when the best engineers from Thermalright decide that it's time to leave a stagnant company who refuses their ideas? They gather their intellect and begin Prolimatech. Unlike other companies that have formed from the staff of another, Prolimatech didn't decide to leave their former home and release another mundane mainstream product. The Prolimatech Megahalems offers everything former projects (like the Thermalright Ultra-120 eXtreme) featured, but then adds new engineering where there were improvements needed.

The Prolimatech Megahalems uses a very dense array of aluminum fins which are split down the middle to form two separate heatsink halves. The Megahalems is comprised of six heat-pipe rods, which span to each side and offer twelve total cooling ends. The nickel-plated copper base secures firmly to the CPU with a proprietary mounting clip system. This mounting system, which I am pleased to report is the most effective clip mechanism I've ever used, offers tremendous contact pressure while completely removing the chance of processor movement or sliding.

Aside from a very impressive alloy mounting system, the Megahalems includes two standard-fit 120mm cooling fans. These fans offered exceptional performance with nearly no audible noise, but the hardcore overclocker and performance enthusiast will certainly want to exchange these parts for something more powerful. Benchmark Reviews has tested the Prolimatech Megahalems with both the included fans and a single Yate Loon D12SH-12 (88 CFM @ 40 dbA) for comparison.

EDITORS NOTE 29 March 2009: The ProlimaTech Megahalems retail kit does not include two cooling fans, although the kit we received did.

Megahalems Specifications

• Heatsink Dimension: (L)130mm X (W)74mmX (H)158.7mm
• Heatsink Weight: 790g
• Heatpipe Ø: 6mm X 6pcs
• Fan: (2) two 120mm x 120mm x 25mm
• Fan Speed: 800~1200 RPM
• Noise Level: (dBA) Below 26 dBA
• Air Flow: 57 CFM

Prolimatech includes both LGA775 and LGA1366 mounting kits with the Megahalems, making it Intel-processor friendly (and specific). Because the Megahalems is just receiving the final packaging revisions before shipping retain, the full-version of the Megahalems kit could potentially include support for socket AM2/AM3.

Thermal Interface Material Application

Over the past several months, I have read an unreasonable number of discussion forum posts which offer inaccurate and often times incorrect information. It's not really all that surprising to read poorly conceived information on the Internet, which seems to be a anonymous means of passing off opinion for fact. As a general rule we don't let too many things go untested, and the advice of wanna-be experts is not doing the hardware enthusiast and overclocker community any good. In this article, Benchmark Reviews dispels myth and establishes fact on the topic of proper application in our Best Thermal Paste Application Methods article.

After we wrote our 33-Way Thermal Interface Material Comparison article, 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.

Surface Finish Impact

Here's the part I've been waiting to reveal... the importance of surface finish in relation to the impact on thermal conductivity. CPU coolers primarily depend on two heat transfer methods: conduction and radiation (heat-pipes also add convection). This being the case, let's start with conduction as it related to the mating surface between a heat source and a cooler.

Because of their density, metals are the best conductors of thermal energy. As density decreases so does conduction (of heat), which relegates fluids to be naturally less conductive, and gases as virtually non-conductive. So ideally the less fluid between metals, the better heat will transfer between them. Ultimately though, this means that the perfectly flat and well-polished surface (Noctua NH-U12P) is going to be preferred over the rougher and less even surface which required more TIM to fill the gaps (Thermalright Ultra-120 eXtreme).

Heat radiation is different however, and requires exactly the opposite. Because gases (air) are naturally poor heat conductors, surface area of the heatsink is key to the cooling performance through convection. This type of cooling is what you commonly see in automobile radiators, which utilize large arrays of metal fins to radiate heat to be drawn away by a fan. The same is true for the CPU cooler, which needs as much surface area as possible to optimize it's radiative effects. OCZ and others have recognized that the surface of a heatsink does not have to be the sum of its overall size. By adding dimples and bends, the surface area is increased without growing the overall dimensions.

To sum it all up, science teaches us that a smooth flat mating surface is ideal for CPU coolers so that less Thermal Interface Material is used. Because these coolers are using fans to force air over the heatsinks fins, the overall surface area of those fins should be as large and uneven as possible. In the next section we'll find out just how well all of these principles worked for our collection of test products.

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 top four most thermally conductive elements. However, without knowing the thermal conductance of these elements you might think 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. Aluminum is the least expensive top-tier metal, which explains the popularity. 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 conductors.

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.

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...

LGA1366 Testing Methodology

Benchmark Reviews has been obsessed with testing CPU coolers over the past year. 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 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 article is going to be a perfect example of that principle, although certain tenants still hold true. Benchmark Reviews continues to test CPU coolers using the stock included fan (whenever applicable), and then replaces it with a high-out fan for re-testing.

Manufacturers are not expected to enjoy this sort of comparison, since we level the playing field by replacing their included fan with a common unit which we then use for every CPU cooler we test. Manufacturers regularly include fans with their CPU cooler products, and more often than not these fans are very high RPM units which offer great airflow at the expense of an obnoxiously loud noise level. By using the same model of cooling fan throughout our testing, 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 CPU cooler performance and we believe that you'll feel the same way.

Testing was conducted in a loosely scientific manner. Ambient room temperatures levels were held to within one degree of fluctuation measured at static point beside the test equipment with a calibrated digital thermometer. All coolers had their original manufacturer-supplied thermal material removed and replaced with a product of our choosing listed in the support equipment section below. Each product then received the same amount of Thermal Interface Material (specified below), which amounted to roughly a BB-sized drop placed onto the center of the CPU. The CPU cooler product 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. EVEREST Ultimate Edition v5.00.1016 by Lavalys was then utilized to create core loads and measure each individual CPU core temperature. It's important to note that software-based temperature readings reflect the thermistor output as recorded by 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 product itself 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.

One unfortunate problem is that CPU's report temperatures as a whole number and not in fractions. This in turn causes the motherboard BIOS and subsequent software applications such as EVEREST to also receive whole-number reports. Thankfully, EVEREST also does offer averages in 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 18~19°C, this would not be enough to cause a noticeable impact on our test results since only the thermal difference is reflected in the 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.

Test System

Motherboard: Gigabyte GA-EX58-UD4P (Intel X58/ICH10R Chipset) with version F7e BIOS
Processor: Intel Core i7-920 BX80601920 2.667 GHz (overclocked test operate at 3.60 GHz 1.35V)
System Memory: OCZ 6GB 1600MHz CL7 DDR3 OCZ3P1600LV6GK
System Drive: OCZ Vertex 120GB SATA SSD OCZSSD2-1VTX120G
• Optical Drive: ASUS BC-06B1ST Blu-Ray Disc Optical Combo Drive
• Enclosure: Cooler Master ATCS 840 Computer Case RC-840
• PSU: Antec TruePower Quattro 850W TPQ-850
• Grpahics: ZOTAC GeForce 9800 GTX+ Zone Edition (liquid cooling looped into X58 Northbridge)
• Monitor: Honeywell 22-Inch LCD Monitor MT-SY-HWLM2216
• Operating System: Windows XP Professional SP-3 (optimized to 16 processes at idle)

Support Equipment

• OCZ Freeze Thermal Interface Material (No curing time necessary or given)
• Yate Loon 120mm cooling fan, model D12SH-12 (88 CFM @ 40 dbA)
• Xigmatek CrossBow ACK-I7361 (supports xxxx1 / xxxx2 / xxxx3 cooler models)
• Xigmatek CrossBow ACK-I7363 (supports xxxx4 / xxxx5 / xxxx6 cooler models)
• EVEREST Ultimate Edition v5.00.1016 by Lavalys

All of our tests are now conducted using only the vertical motherboard orientations traditional to tower computer systems. 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 sixty 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. Once the testing has been completed at the stock processor speed, Benchmark Reviews turns up the voltage on our Core i7-920 processor and overclocks to 3.6GHz using a 1.35V vCore. When the system restarts, we start our testing over from the beginning and allow a minimum of sixty minutes of loading before taking our readings.

Stock Cooling Fan Results

Benchmark Reviews tries to cover every angle, but sometimes it's just not possible given our time constraints. Our past 'Best CPU Cooler Performance' series have largely focused on the Intel Core 2 Duo/Quad LGA775 socket, and while the results are relevant to users of those processors, 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 size, they also contain the processor cores in different locations. Simply stated: what worked well on a Core 2 platform may not work very good with Core i7.

When it comes to personal computers, you could probably divide users into two separate groups for almost any one topic. This article is no different, and those two groups include both enthusiasts and overclockers. Hardcore overclockers and serious hardware enthusiasts may not consider the stock cooling results very interesting, but they're welcome to skip ahead into the next section where we add a high-performance fan and then add overclocked values. Believe it or not though, some people are on a budget and don't want or have the extra money to spend on aftermarket cooling fans or an additional bolt-through kit; sometimes they just want good cooling right out of the box. This section is for them.

In regards to fan noise, there are those of us who want it quiet while other will tolerate an eardrum-ringing whine. Since noise is a problem and not a solution, I believe that most enthusiasts want as much performance as they can get without additional tweaking and time-intensive modifications. That's what this test section is all about: how the cooler performs out of the box. For the "Stock Cooling Fan" results, Benchmark Reviews tests our Q1-2009 collection of LGA1366 CPU coolers for this article using the following criteria: Each cooler is tested with the manufacturer-included fan, so that performance will be relevant to consumers using the product in stock form.

Please keep in mind that a product that finishes at the top of the stock fan list isn't going to be relative if you plan on overclocking your processor or invest in a different cooling fan. 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.

The best CPU coolers Benchmark Reviews has tested in stock form for the LGA1366 socket is very different from the results we've seen in past LGA775 tests. Some Core 2 favorites fall down a few places, while others remain relative. The performance results position the coolers in the following order, with the temperature difference beside them:

While the Titan FINRIR occupies the top position on our stock-fan chart, it's largely in-part because of the cooling fan offering extremely high-volume output, although the cooler offers extremely good design otherwise. Similarly, the Prolimatech Megahalems enjoys a similar advantage because it includes* two low-noise 120mm cooling fans and at the same time features an effective product design. The Zalman CNPS9900 LED gets its performance from the high-output high-noise integrated fan, along with a dense array of copper fins. The Thermalright Ultra-120 eXtreme is an old crowd favorite, and matched with a (finally) included 120mm fan it does very well. For the size, the Cooler Master V10 TEC is pulling its own weight, but hopefully we see better results in the next sections. Equally impressive and half as large is the Cooler Master Hyper Z600, followed closely by the Xigmatek Dark Knight S1283V which features a bolt-through kit and decent cooling fan. The Xigmatek HDT-S1284 continues to offer very good performance out of the box, with the Spire TherMax II SP679S1-PCI right behind it.

* EDITORS NOTE 29 March 2009: The ProlimaTech Megahalems retail kit does not include two cooling fans, although the kit we received did.

The next group of coolers doesn't quite make it into the top positions, but still offer great performance. The Noctua NH-U12P sacrifices cooling performance for a pair of completely-silent 120mm fans, but still manages to make our top-ten. The Cooler Master V8 performs well enough, but the stock fan is meant for low-noise and not high-output airflow. The low-volume low-noise fans included with the OCZ Gladiator Max and OCZ Vendetta 2 push them to the end of our top-performance LGA1366 coolers. From this point on, the performance gets ugly.

Because the CoolIt Domino ALC offers three fan settings, we felt it was appropriate to use the low fan setting for the stock comparison. Although the Domino ALC was completely silent, almost scary silent, it barely kept up with the other high-end coolers when applied to a stock Intel Core i7-920 processor operating at 2.66 GHz. There were only two products which did worse... a lot worse. The Arctic Cooling Freezer Xtreme performed miserably, primarily because the cooling fan is meant for low-noise and not high-output airflow, but also because the contact base was nearly half the size of the processors IHS surface. The test results actually began to scare me, as the core temperatures occasionally reached 60°C. For comparison purposes, the stock Intel LGA1366 thermal cooling solution that comes included with retail processors was tested. What little nerve I had left after watching the Arctic Cooling Freezer Xtreme was now gone, as the Intel LGA1366 cooler often found itself of the wrong side of 70°C core temperatures. Thankfully, I only had to test it once.

There were a few products excluded from our stock fan results, simply because they don't include a fan with the kit. The Xigmatek Thor's Hammer S126384 is one example, and so is the Thermolab BARAM. If you want to see how these coolers do when they have a high-volume cooling fan attached, please continue into the next section.

High-Output Fan Results

This section uses the high-output Yate Loon D12SH-12 cooling fan on each product tested. Because of the size and design constraints, a 120x120x25mm fan is as large as we can go with our collection of coolers. We are aware that much more impressive fans are available, such as the 120x120x35mm screamers that require a bolt-on kit to retain them. But in my experience, the Yate Loon D12SH-12 is one of the best 120mm cooling fans available in regards to the noise to performance ratio. The D12SH-12 cooling fan forces an impressive 88 CFM of air at a moderately noisy 40 dbA.

In our recent review of the Xigmatek Thor's Hammer S126384 cooler, Benchmark Reviews used the Scythe Kaze-Jyuni Slip Stream 120mm cooling fan (model SY1225SL12H) along side the Yate Loon D12SH-12. Although Scythe claims the Kaze offers 88.11 CFM, I had a difficult time believing the stated specification when the results were always in favor of the Yate Loon product. Regardless, the Kaze series is quite popular with enthusiasts and the SlipStream does do well to provide sufficient airflow without all the irritation of noise... but Benchmark Reviews isn't going to use it for testing in this article.

Even though the CoolIT Domino ALC is a water-cooled solution, I thought it would be interesting to measure the performance against our collection (although this time the fan was switched onto the 'high' setting). The Arctic Cooling Freezer Xtreme doesn't allow the fan to be replaced, which removes it from this section of tests. The Cooler Master V10 was also not included in these results because there are two fans (in addition to TEC cooling technology), but it's included in the next section of overclocked results. All of the other CPU coolers received a single Yate Loon D12SH-12 cooling fan, and finish the testing in the following order:

It becomes evident that there's a point of diminishing returns for every CPU cooler, and when over-cooled the results collide closely together. Although the 2.66GHz Intel Core i7-920 processor does a decent job of separating the crowd, there's still only about 7°C between the fifteen coolers we tested. Tt's a good bet that any one of these well-designed products will cool an overclocked system extremely well, but these days only the very best will do. Much like the Thermal Interface Material testing we have done for our upcoming follow-up article, high-performance products are all beginning to perform at nearly the same levels. Eventually, I expect to see the same technology used in all cooling products with the difference being the application. This is where experience comes in handy, and we've shared some of this with you in our Best Thermal Paste Application Methods article. Remember, less is more when it comes to thermal paste, and soon CPU coolers may offer the same paradigm.

So far, the Prolimatech Megahalems has dominated both the stock and high-output fan tests, which certainly doesn't make two products tied for second-place very happy. The Thermalright Ultra-120 eXtreme and Xigmatek Thor's Hammer S126384 are neck and neck with each other, but still a few degrees behind the Megahalems cooler. Titan's FINRIR also makes it into the top of the list again, with the all-copper prototype of the HDT-S1284 coming in right behind it. Some coolers didn't move in relation to the previous tests, and keep the same order in the lineup.

The Cooler Master Hyper Z600, Xigmatek Dark Knight S1283V, and Xigmatek HDT-S1284 all keep the same positions and order, but also improve a few degrees with the high-output Yate Loon fan. Because the OCZ Gladiator Max and Spire TherMax II both have loosely packed fin-sinks, there's really not much the additional airflow will help. Unlike our LGA775 tests, the Noctua NH-U12P seems to be coming up short on ultra high-end cooling performance. While not at all bad in comparison, the core temperatures were often seen nearing 48°C under full load; which is still 6°C more than the Megahalems delivered. Last on our list was the Cooler Master V8, which cools well enough, but may not be up to the task when we add some voltage and overclock the processor... which is exactly what happens in our next section.

Overclocked Test Results

Here it is, the only section that matters in the world of high-performance overclocking and aftermarket CPU coolers. After all of our stock testing was complete, we removed the 2.66GHz Intel Core i7-920 processor and spend an hour lapping it flat with super-fine 1200 grid wet-sanding paper on a thick piece of glass. Once the Integrated Heat Spreader (IHS) exposed the copper finish, we switched to ultra-fine 2000 grit wet-sanding paper. To add a final buffing finish, the surface was wet-sanded with ultra-fine 2500 grit and then polished with liquid finishers. When the Core i7-920 was reinstalled into the X58 test platform, the voltage was raised to 1.35V and pushed to a moderate 3.6GHz overclock. A much higher overclock was available, but because of failure or instability risks, Benchmark Reviews tests at the most stable speed possible to avoid crashes and potential test failures. Remember, they all must pass testing, or the testing must be redone completely.

The core temperatures all immediately increased by nearly 20°C across the entire collection, even with the Yate Loon D12SH-12 huffing and puffing. All kits used either an included or aftermarket bolt-through kit for mounting the cooler and creating good contact pressure. After each test run was completed (usually about one hour), the cooler was removed and the contact spread was inspected before being cleaned and re-installed for another test. Doing this revealed an peculiar trend, which make the distinction between LGA775 and LGA1366 performance more understandable.

Because of the slightly spread-out core placement on a Core 2 Quad or Duo processor, most triple-piped HDT cooler would make directly-aligned contact with the cores through the IHS. However, when it comes to the Core i7 series, the processor cores line-up better with four-piped HDT coolers (or at the outer edge of the center heat-pipe in the three-piped HDT cooler). Conversely, coolers with a solid base are not effected by either platform, so long as they're big enough to saturate the contact surface. Making matters a little more complicated is the orientation of the Core i7 processor series, which is restricted to comply with the Intel-designed horizontally-aligned rectangle shape (not square like LGA775 processors). The 32mm tall by 35mm wide Core i7 processor is more sensitive to how a cooler is mounted to it, and care must be take to ensure the IHS is fully covered.

The overclocked Intel Core i7-920 processor helped to separate our large collection of LGA1366 cooler by more than 10°C between them. Benchmark Reviews is confident that these results match those of users with the same system and configuration, but because our tests route the video card and X58 Northbridge through a water-cooling system to avoid radiant heat corruption in our results, your own results will be slightly higher. In order of final performance, these are the Best CPU Coolers for the overclocked LGA1366 Core i7 platform:

All of the top performing CPU coolers have a few things in common, although some are better designed than others. The mounting system on the Prolimatech Megahalems uses an excellent bolt-through system with keyed alloy plates to ensure a perfectly centered cooler, similar to the Xigmatek Crossbow kit we use for other coolers. The Thermalright Ultra-120 eXtreme also uses a bolt-through kit, as does the Cooler Master Hyper Z600 and V8... so contact pressure is extremely high for all of these products. Half of our CPU cooler collection have very flat mirror finishes for the contact surface, whereas the other 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. The Domino matches a flat polished surface to water cooling. In my opinion, every single product on this chart is an excellent cooler, but only the top few can be considered the Best CPU Cooler.

The Prolimatech Megahalems is the standout top-performer, with a total adjusted temperature of 37.73°C over ambient. Nearly three degrees away is the Thermalright Ultra-120 eXtreme and Xigmatek Thor's Hammer S126384. All three of these coolers are phenomenal performers, and deserve the title of Best CPU Cooler for the Intel Core i7 / LGA1366 socket.

The Titan FINRIR, all-copper Xigmatek S1284 prototype, Thermolab BARAM, CoolIt Domino ALC, Cooler Master Hyper Z600, and The Xigmatek Dark Knight S1283V are all trailing a few more degrees behind the leaders. All of these coolers will work extremely well in overclocked systems, and given the right circumstances might perform just as well. Some of these coolers will accept a second fan, further improving results, while other are limited to only one. Taking cost into consideration, the field can been reduced to only a few real contenders.

Although it performs within 9°C of the leader, the Cooler Master V10 TEC was not nearly as impressive as it looks. I was warned by Cooler Master that the TEC cooling technology only kicks in at higher temperatures, but I'm not clear on what that magic number is. If it didn't 'turn-on' during this test, I'm not sure when it will. Additionally, I wondered why they would make it wait for high temperatures, when even moderate temperatures deserve good cooling, too. The OCZ Gladiator Max, Noctua NH-U12P, Vendetta 2, and Spire TherMax II all finish out the high-performance group of coolers, and trail up to 10°C behind the leader.

The Cooler Master V8 does well enough, but the limited fan potential locks it down to a single 120x120x25mm unit. It the V8 wasn't so large, I might be a little more forgiving, but since it occupies so much space I become more critical. Without fail, there's always an exception to the rule for one particular product. For this section, it's the Zalman CNPS9900 LED. Sure, it's unfair to judge the CNPS9900 against a collection of larger Yate Loon cooled products, but the integrated SuperFlo-bearing 92mm fan sure manages to hold its own against the more formidable opponents. I didn't add the Zalman CNPS9900 LED cooler into these results to be cruel, but instead show how a small, well-designed cooler can compete with the larger products if the manufacturer does their engineering homework.

In the next section, I offer my final thoughts on the future of CPU coolers.

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 mounting kits whenever possible.

CPU coolers made for the 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'. If you use an LGA775 cooler on a LGA1366 socket, your missing out on 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 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.

Prolimatech Megahalems Conclusion

Intel has made its mark with their LGA775 'Socket T' interface. For enthusiasts and overclockers, there's still plenty of life left in the old platform. As of March 2009 the quad-core Q8200 and Core 2 Duo E8400 each sell for around $164.99, while the price on a Core 2 Quad Q6600 has actually increased to $198.99; thus proving that popularity for the LGA775 platform still exists. All of these products provide excellent value, and give hardware enthusiasts a reason to continue using or consider P45 and X48 chipsets. Furthermore, AMD has rebounded nicely and also offers competitive products with their latest Phenom II launch. As of March 2009, the Phenom II X4 940BE is sold at NewEgg for $200 and the triple-core Black Edition Phenom II 720 is available for $147, but by using the Benchmark Reviews price comparison tool we discovered several other deals offered.

The Megahalems CPU cooler kit Benchmark Reviews received for testing included two generic 120mm cooling fans (although the retail kit includes just one fan) and mounting hardware for LGA775 and LGA1366. Although the stock fans were more than enough to tame most warm-blooded systems, Prolimatech confines the mounting kit to Intel processors. Benchmark Reviews offers an excellent guide for beginners wanting to overclocking their CPU, so join in and see how far you can stretch that dollar! Ideally the Megahalems would have fit in nicely with our past LGA775 tests, but I've already wrapped up my testing for that platform back in the Best of Q4 2008 Conclusion. As for the new LGA1366 platform, here are my suggestions:

For absolute performance without regard for cost, my recommendation goes to the Prolimatech Megahalems. This is a product designed by the former Thermalright engineering team, and takes the best design aspects into consideration to produce one phenomenal product. The mounting base is unparalleled by any other I've tested, which delivers extraordinary contact surface pressure between the processor and the mirror-finish on the Megahalems. Unfortunately, Prolimatech isn't a household name (yet), and major online retailers like NewEgg haven't started to carry their products. This will make finding a Megahalems kit extremely difficult for the top-shelf overclocker, but it won't hold back our Golden Tachometer Award.

As of April 2009 only FrozenCPU is selling the ProlimaTech Megahalems, but if you don't find it available I can suggest two alternate recommendations. The Thermalright Ultra-120 eXtreme has a long history of cooling high-temperature overclocks, and the kit I tested (which was furnished by Intel Corporation for the Core i7 and X58 platform launch) came with a smoother contact surface than the kit I received from Thermalright for the LGA775 platform. Although the Intel-supplied kit had a separate 120mm fan and retaining kit, I don't believe these are included with retail packages. Offering identical cooling performance was the Xigmatek Thor's Hammer S126384, which is available at NewEgg for $64.99. The CAC-SXHH7-U01 kit comes with the new CrossBow ACK-I7363 mounting system, and has the ability to fit two 120mm fans or either 25mm or 35mm depths. Between the two, the Thor's Hammer offers greater performance under the most intense thermal loads.

Beyond these three performers, there's only a handful of other CPU coolers I might consider worthy of high-temperature overclocking projects. The Titan FINRIR TTC-NK85TZ and Thermolab BARAM are two new products unlikely to be found in North American stores but still deserve your attention. More likely to be a favorite among online retailers will be the Cooler Master Hyper Z600 RR-600-NNU1-GP kit for $59.99 and Xigmatek Dark Knight S1283V which sells for $39.99 at NewEgg. Each of these kits offers LGA1366 compatibility, and each comes with a capable cooling fan (although the Hyper Z600 can fit four 120mm units).

Pros:

+ Best CPU Cooler for LGA1366 Core i7 platform
+ Tremendous thermal cooling performance
+ Unmatched mounting system design
+ Well-designed split heatsink construction
+ Includes two 120mm cooling fans
+ Includes Prolimatech carbon-based premium TIM
+ Capable of fitting two cooling fans on heatsink

Cons:

- AMD Mounting systems not included
- Limited manufacturer support and warranty
- Slow availability reaching retail markets

Excellence Achievement: Benchmark Reviews Golden Tachometer Award.

If you have constructive suggestions, Benchmark Reviews encourages you to leave comments and questions in our Discussion Forum.

Related Articles:

• Zaward Sylphee ZCJ003 CPU Cooler
• Thermaltake Frio CLP0564 CPU Cooler
• Coolit Vantage A.L.C. CPU Cooler
• Zalman CNPS9900 MAX 135mm CPU Cooler
• Best CPU Cooler Performance Intel/AMD Q1-2010
• Kingwin RVT-12025 HDT CPU Cooler
• ProlimaTech Super Mega Heatsink Preview
• ASUS P5Q3 LGA775 Intel P45 ATX Motherboard
• Cooler Master V6GT CPU Cooler
• Best CPU Cooler Performance LGA1366 Q2-2009