Thor's Hammer S126384 Heatsink Review

Overclockers are always looking for the best CPU cooler made, and Benchmark Reviews has taken a new approach to determining this for them in every Cooling article we publish. Most enthusiasts are already very familiar with the Vendetta 2, TRUE, and HDT-S1283, but the landscape is going to change with the Xigmatek Thor's Hammer S126384 CPU cooler. Benchmark Reviews compares the top coolers using the Yate Loon D12SH-12 and Kaze SlipStream 120 on an overclocked and over-volted Intel Core i7-920 Processor.

Xigmatek has been quick to release several new products lately, all of which offer a twist on their popular HDT-S1283 design. The latest designs all still offer HDT (Heat-pipe Direct Touch) architecture, but they introduce new features which set them apart from the large product family. Specific to the CAC-SXHH7-U01 product SKU, Xigmatek introduces a double-layer HDT design with overlapping rods. Thor's Hammer is not meant for the average system, as its designed to perform best under extremely high thermal loads. With a few benchmarks to prove the initial claims, we will soon see how well the S126384 performs.

In this article, which is meant to tide over some of the hard-core enthusiasts before we publish the upcoming Best CPU Cooler Performance - Q1 2009 round-up, Benchmark Reviews will add a moderate overclock to the Core i7 and use two different enthusiast-grade fans. While the difference from 2.66 to 3.33GHz offers a moderate overclock, the increase in voltage to 1.35V helps simulate higher overclocks without compromising our test system (which must successfully test over twenty coolers without a hardware problem).

New to Xigmatek CPU coolers is the included bolt-through kit. Since the Xigmatek Thor's Hammer S126384 includes a Crossbow ACK-I7363 mounting kit with it, we decided to offer the same benefits to the other coolers in our test collection. Thermalright still uses the cumbersome screw-down kit for their Ultra-120 eXtreme, but we've added the ACK-I7361 to the OCZ Vendetta 2. In addition to the high-pressure mounting clip systems, our tests will also ignore stock fan results; primarily because the CAC-SXHH7-U01 kit doesn't come with one, and neither does the TRUE. OCZ includes a rather mundane low-noise fan with the OCZTVEND2, but it doesn't compare to the Kaze SlipStream 120 or Yate Loon D12SH-12 we tested with.

About the company: Xigmatek Co., Ltd.

XIGMATEK, a European company, was established in 2005 with the aim of becoming one of the world leaders in the Thermal field. In XIGMATEK, the major members of management have many years experience in Thermal industry, PC, manufacturing and other applications. With our fruitful experience, we have full confidence that we can provide not only the best, reliable, environmental and performing Thermal/Cooling systems but excellent service also to fulfill global user demand.

Purpose and targets of becoming one of the worlds leaders in thermal PC Industry were set for Xigmatek Co. Ltd in 2005, the founding year! To ensure reaching this project aim, Xigmatek's management followed up with hard work, experience and customer friendly business style.

Honing one of the world's most efficient manufacturing operations, Integration Presence in major economic regions, being tied up with most important strategic alliances between suppliers and academia and further majority investments in R&D are some of Xigmatek's aggressive enhancement strategies.

Combining the cream of product designers, R&D engineers and technical people (main team in Germany) Xigmatek is proud and full of confidence to offer excellent quality products and service to cover the customers requirements and demands. Within the standard channels as the consumer market and the distributing electrical appliances, Xigmatek will keep on focusing on development and set up even new sales channels to comply with ever-changing demands and requirements. Several years of experiences company background in Thermal IT industry provides our customer the best, reliable, environmental and performing Thermal/Cooling Systems including excellent Service to fulfill global users and customers demands.

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...

Xigmatek CAC-SXHH7-U01 Cooler

Our first look at the Xigmatek Thor's Hammer S126384 reveals a complex array of densely double-stacked fins atop a double-layer of heat-pipe rods. The finish is comprised of a black nickel coating, which makes the S126384 surprisingly heavy at 800 grams (before mounting clip brackets). Xigmatek doesn't include a fan, because they feel that this is their flagship cooler and it should be matched with a premium after-market fan of the overclockers choice. While the CAC-SXHH7-U01 kit comes with enough rubber retaining plugs for two fans, we will compare our group with on one forward mounted fan blowing to the rear of the case.

The concept behind the S126384 is that it relies on ultra-heavy thermal loading to take advantage of its double-layer heatpipe architecture. Because of the very dense fins array, and the four-pipe contact base, Thor's Hammer is really best suited for larger AMD Phenom II and Intel Core i7 processors which feature a larger IHS (Integrated Heat Spreader) surface area. We tested the group on the Core i7/X58 platform, but in retrospect the AMD Phenom II X4 940 Black Edition probably would have been more fun and offer a better contact surface with the enlarged base of these coolers.

Thor's Hammer S126384 Features

• H.D.T. (Heat-pipe Direct Touch) technology
• Double-layer HDT and double-heatpipe performance
• Black-Nickel plating throughout the entire cooler
• Anti-vibration rubber fan mounting design
• Includes Crossbow ACK-I7363 bolt-through mounting kit
• Passive cooler design with optional fan installation for extra cooling

CAC-SXHH7-U01 Specifications

• Product Name: Thor's Hammer S126384
• Product Number: CAC-SXHH7-U01
• Outside Dimension (W) x (H) x (D) mm 120 x 90 x 160
• Heat Sink Material: Aluminum Alloy
• 4pcs Φ8mm Primary heat-pipe group
• 3pcs Φ6mm Secondary heat-pipe group
  
  

All forty-nine of the blackened aluminum-alloy fins are met by the seven heat-pipe rods, which turn into fourteen different heat-pipe cooling ends. Because of the staggered fins array, high overclocks could potentially see better cooling from the static pressure a 120x120x35mm fan can provide. The 120x120x25mm profile is standard for most Xigmatek coolers, but don't feel limited to using this profile if your case can afford the space. The total width with two (120x120x)25mm fans is 140mm, which is slightly longer than the width, but adding 35's would make this a very long cooler.

The Thor's Hammer S126384 is meant to compete with the most elite CPU coolers known to the industry, but that's what every product we test pretends to claim. In our next few sections, we'll peek at how well the S126384 does against the Thermalrigh Ultra-120 eXtreme and the OCZ Vendetta 2 CPU coolers.

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 principal 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 principals worked for our collection of test products.

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 principal, 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)
• Scythe Kaze-Jyuni Slip Stream 120mm cooling fan, model SY1225SL12H (88.11 CFM @ 33 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.

Test Results: Kaze Slip Stream

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. 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.

Scythe Kaze-Jyuni Slip Stream 120mm cooling fan, model SY1225SL12H, claims to offer 88.11 CFM. After testing with so many products for so long, I had a difficult time believing the stated specification when the fan barely emitted 33 dBA. 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.

After an hour of sustained loading on each of the four Core i7 processor cores, the temperature has plateaued. In all of our tests, TurboBoost was turned off to avoid core-to-core irregularities. When the dust settled, the Xigmatek Thor's Hammer S126384 came out slightly ahead of the pack, with an adjusted temperature (average of four cores minus ambient) of 44.05°C. Not too far behind was the Thermalright Ultra-120 eXtreme with 45.33°C for a 1.27°C difference after three tests. Last in the group is the OCZ Vendetta 2, which doesn't perform so well with extreme temperatures like it does with mild (or no) overclocks. The 49.73°C delivered by the OCZTVEND2 falls 5.68°C behind Thor's Hammer, and 4.3°C behind the TRUE.

I can see why so many people like the Kaze SlipStream 120. The small center hub may not be as efficient as the IXTREMA fans found on the SilenX IXC-120HA2, but they sure do blow more air! In the next section, Benchmark Reviews secures the big bad wolf to help blow the heat down on our toasty little products.

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.

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.

Xigmatek S126384 Conclusion

Intel has made its mark with their LGA775 'Socket T' interface, but the age of Phenom II and Core i7 is upon us. For enthusiasts and overclockers, there's still plenty of life left in the old platform. Prices on the Intel Core 2 Quad Q8200 have dropped to $169.99 as of mid-February 2009, but the very competitive AMD Phenom II X3 720 has just launched at the same price and offers unrestricted overclocking. All of these products provide excellent value, and give hardware enthusiasts a reason to patronize DDR2 systems for a while longer. Furthermore, there are so many excellent CPU coolers to choose from that you can't go wrong with any one of our top choices and overclocking the CPU has never been so available to the masses.

Even when you add plenty of additional voltage to a high-end processor, only three small degrees separate the very best top-end CPU coolers. Because the technical architecture and design concepts have been converging for so long now, it's not really all that surprising to see similar results for similar products. The Intel LGA1366 socket is home to some hot processors for the X58 platform, and even when you remove the surrounding heat sources (we use the Gigabyte GA-EX58-EXTREME motherboard with a water-cooled Northbridge looped into the ZOTAC GeForce 9800 GTX+ Zone Edition video card), you still get some very high temperatures.

At the time of this article the Xigmatek Thor's Hammer S126384 kit was available at NewEgg for $64.99, which directly competes with the most elite CPU coolers currently sold. For better deals, you can use our Price Comparison Tool to find the best bargains once they're on the shelves.

This premium kit builds a 'top shelf' reputation by including the Crossbow ACK-I7363 mounting kit and stylish packaging, while offering every hardware accessory needed to propel Thor's Hammer into mainstream integration. It's not the most affordable cooler we've found, nor does it offer the best 'bang for the buck' ($17.99 Kingwin RVT-12025), but it tops our charts when the temperatures were at their highest and can accommodate two cooling fans. The combined appearance and craftsmanship help earn the Benchmark Reviews Golden Tachometer award for the S126384, but it's the phenomenal cooling performance that really seals the deal.

Pros:

+ Meets and exceeds our previous best performance
+ Seven total large-gauge heat-pipes
+ Staggered aluminum alloy fins offer excellent dissipation
+ Includes bolt-through mounting kit
+ Cools the most overclocked computer systems

Cons:

- Premium pricing
- No spare soft rubber T-clip supplied
- Does not include cooling fans

Ratings:

• Presentation: 9.50
• Appearance: 9.75
• Construction: 9.50
• Functionality: 10.0
• Value: 7.25

Final Score: 9.0 out of 10.

Excellence Achievement: Benchmark Reviews Golden Tachometer Award.

But before Benchmark Reviews publishes the results for our upcoming Best CPU Cooler Performance - Q1 2009 round-up, allow me to offer my final suggestions for LGA775 CPU coolers. I determined this standing by taking five variables into account: performance, cost, installation, construction, and availability. Obviously performance has the most impact on my decision, but if two or more coolers perform the same and one costs half as much it begs to reason that I favor the more affordable product. Furthermore, well-built and easy-to-install products get my vote over something less convenient. Finally, rare and hard-to-find CPU coolers are less desirable than readily-stocked products.

• OCZ Vendetta 2 (OCZTVEND2): Consistent top-performer with the OCZTFORCV mounting kit available for maximum contact pressure. As of February 2009, the OCZTVEND2 kit sell for $49.99 at NewEgg.
• Kingwin RVT-12025: A clone of the HDT-S1283, but with slightly lower-volume fan included. With a $17.99 price tag, this is the most affordable top-performance product available; leaving money to upgrade the fan and mounting kit.
• Xigmatek HDT-S1283: The grandfather of HDT still performs at the top of our charts, and the Xigmatek CrossBow kit ACK-I7751 only costs an extra $6.99. Presently the HDT-S1283 sells for $36.99 ($26.99 after rebate).
• Vantec AeroFlow 120 VAF-1225: Clones the HDT-S1283 design and cleans-up the appearance with a well-polished look. Currently the VAF-1225 sells for $34.99 from NewEgg, and accepts the same bolt-through kits.
• Cooler Master Hyper Z600: This large multi-fan ready cooler has enormous potential for extreme overclocking. The RR-600-NNU1-GP package is available for $59.99 and comes with it's own LGA775 and LGA1366 bolt-through kits.
• Sunbeam Core Contact Freezer CR-CCTF: Four exposed heat-pipes offer very good cooling, even with the stock fans. A proprietary clamp-down system keep the CR-CCTF in place. Available at NewEgg for $39.99 ($29.99 after rebate).
• Noctua NH-U12P: Although this is our best-performing CPU cooler, it is also the hardest to find. NewEgg offers the updated 'Second Edition' NH-U12P SE1366 for $84.99 which includes two fans and bolt-through kits for LGA775 and LGA1366.
• SilenX IXC-120HA2: Similar to the CR-CCTF, but supports two 120mm fans. SilenX includes one of their iXtrema Pro Quiet fans, which I enthusiastically endorse. NewEgg lists the SilenX IXC-120HA2 for $49.99.
• Thermalright Ultra-120 eXtreme: Known as the 'TRUE' this cooler needs some extra attention and requires that you purchase fan(s) separately, but otherwise performs very well. At $79.99, very few retailers still offer the TRUE online.
• Cooler Master V8: Performs well with the included 120mm fan, but performs even better with the Yate Loon D12SH-12. The RR-UV8-XBU1-GP kit includes LGA775 and LGA1366 bolt-through components, and sells for $69.99 online.

Please make your suggestions, or leave comments and questions in our Discussion Forum.

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