Best CPU Coolers of Q1 2008

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. We understand that many of our readers have been involved with other community websites for years, and take our test results personally; this was made clear to us when we released our 33-Way Thermal Interface Material Comparison article. So then after months of planning and preparation, we have worked to achieve the most complete source of test results possible, offering irrefutable test results gathered in a controlled environment. The purpose of this article is to document our findings and declare the best and top-rated CPU coolers available as of Q1 2008.

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 effects the overall performance as we test a large segment of products.

Our scope is limited to stand-alone products only, meaning those products which can be installed and operated without additional critical components needed or kit construction. This generally excludes nearly all liquid cooling systems, which may offer better performance than the products we test. Suffice it to say however, the vast majority of gamers and enthusiasts are using air-cooled solutions and therefore we target this article towards them.

Manufacturers are not expected to enjoy this sort of comparison, since we level the playing field by replacing their included fan (whenever applicable) 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.

Before we introduce our newest collection of CPU coolers, let's establish that our tests consist of methods we have determined to be the best for our one singular purpose. Our methodology isn't written in stone, and could very likely be changed or modified as we receive justification (and feedback from the community).

We encourage hardware enthusiasts to utilize the equipment available to them, and select the cooling fan that best suits their needs. Just keep in mind that exceptional cooling performance must begin with the CPU cooler, and end with the cooling fan. It's the foundation of the unit that makes a difference, which is exactly what we're after in this article.

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...

Kingwin RVT-12025

Benchmark Reviews will often times test a product that is very similar to another that we've already reviewed, only with subtle differences separating them. A much less common occurrence is when we see the exact same product wearing, only with a different name. Kingwin is fortunate then to have built their RVT-12025 HDT CPU cooler from a winning mold. Designed from the Heat-pipe Direct Touch technology created by Zaward, and later incorporated into the award-winning Xigmatek HDT-S1283 CPU cooler, the new Kingwin Revolution RVT-12025 is a chip off the old block... a very well established block.

Heat-pipe Direct Touch isn't a new technology anymore, since it's been around as long as Benchmark Reviews has been. But with slightly more than a year behind the design, it's as strong as ever. By removing the metal base from between the CPU's integrated heat spreader surface and the CPU cooler, the heat-pipe benefits by direct contact with the heat-generating surface which results in a more rapid heat and cool cycle for the heat-pipe rod.

When we first put our hands on this technology, we were blown away by how well it performed compared to much larger cooling solutions. There have been many iterations of the Heat-pipe Direct Touch technology since Zaward's original design first introduced in the ZikaRay in early February 2007. Xigmatek later "borrowed" the concept and design of the exposed heat-pipe cooler, and took it to a whole new level with their HDT-S1283. The biggest problem after we made discovered the S1283 was finding a place to purchase the high-performance cooler.

This is where Kingwin fits into the big picture. It's true that their Revolution RVT-12025 CPU cooler and near-clone to the Xigmatek HDT-S1283. It's difficult to find the S1283 stocked in North America, which presents a small problem for overclockers and hardware enthusiasts wanting to make the purchase. Kingwin seized this opportunity, and added their Revolution RVT-12025 to the shelves of popular e-tailers in both the United States and Canada.

RVT-12025 Specifications

Rated voltage: 12 VDC Life expectancy: 50,000 hrs
Connector: 4 Pin with PWM
Heatsink dimension: 120 x 50 x 159 mm
Heatsink material: Aluminum w/ copper base

About the company: KWI Technology Inc.

Kingwin was founded in 1992 as a manufacturer specialized in designing and manufacturing CPU Coolers and Mobile Racks, also with goals to provide our customers with the best Computer Chassis, Thermal Cooling, Liquid Cooling, and Storage Solutions. With the company's core business of Storage Solution units is still growing at a vast rate, Kingwin started looking into the PC chassis industry. To date, Kingwin has always been considered the pioneering company that revolutionized the Storage Solution Industry by bringing out different types and great storage units. The typical and traditional beige and plastic front panel design was replaced buy the excellent and more light and cooler material of the aluminum Storage Solution units. By doing this, Kingwin started growing in the industry and still is growing up to this date.

Xigmatek Red Scorpion S1283

Inheriting a design from the HDT-S1283 it is derived from, Xigmatek's Red Scorpion S1283 offers some additional glamour to the already market-proven cooling solution. With Nickel-plated copper heat-pipe rods and a transparent orange fan with four white LED lights, the Red Scorpion not only performs well but also looks very attractive. Benchmark Reviews has long since been a believer of the excellent performance Heat-pipe Direct Touch coolers have offered, and since the Xigmatek HDT-S1283 has been a fan favorite for almost a year it will be interesting to see how the nickel plating will impact performance.

I was a big fan of the easy installation that came with the first HDT-S1283 design, and it returns with the Red Scorpion. There are anti-vibration rubber latches to minimize vibration and noise, a unique spoiler design to deflect airflow away from motherboard components (or towards them depending on your needs). The push-pin clip system fits both Intel and AMD systems, making it easy to install while offering good performance for users.

In nearly all circumstances the Xigmatek Red Scorpion S1283 is identical in construction and design to their HDT-S1283 CPU cooler. The heat-pipe rods are the same size but now have a nickel plating over them, and the finsink is exactly the same. Notice from the image below that the Red Scorpion S1283 has the surface ground flat and level after the rods are pressed into place. Even in this close-up view, the grain in very minimal and the surface area is very large.

Red Scorpion Features

• H.D.T. (Heat-pipe direct touch) technology
• Anti-vibration rubber design
• Transparent fan with colorful LED lights
• Particular spoiler design
• 3pcs Φ8mm high performance U type heat-pipes
• Light weight
• High performance & easy installation
• 120mm highly efficient PWM fan
• 3 in 1 application: LGA775 push-pin/K8 & AM2 tool-less clip.

S1283 Specifications

• Product Name: Red Scorpion S1283
• Product Number: CAC-SXHH3-U03
• Outside Dimension (W) x (H) x (D) mm 120 x 50 x 159
• Heat Sink Material: Aluminum Alloy
• Fan Dimension (W) x (H) x (D) mm 120 x 120 x 25
• Pulse Width Modulation (PWM) Fan
  • Voltage Rating (V) 12V
  • Speed (R.P.M.) 1000~2200 R.P.M.
  • Bearing Type Rifle Bearing
  • Air Flow (CFM) 72.1~99.6 CFM
  • Air Pressure (mm H2O) 2.6~4.8 mm H2O
  • Life Expectancy (hrs) 50,000 hrs
  • Noise Level (dB) 20~32 dBA
  • Connector 4 Pin with PWM
  • Weight (g) 600g (w/fan)

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.

Kingwin RVT-12025D

Kingwin has had tremendous success with their North American offerings of the Heat-pipe Direct Touch technology. In addition to product clones of the Xigmatek HDT-S1283 with their own Revolution RVT-12025 and, they have also released the RVT-12025D as a North American version of the Xigmatek HDT-S1284. Kingwin's RVT-12025D features 6-gauge copper heat-pipe rods compared to the 8-gauge rods in the HDT-S1284, but otherwise the designs are identical.

When I first learned of the Kingwin Revolution series at the 2008 International CES, I was excited to get my hands on the RVT-12025D because I hadn't seen the design yet. It appeared to have many of the same high-performance characteristics as many other CPU coolers we've seen of it's style, such as the Thermalright SI-128.

In many ways the Kingwin Revolution RVT-12025D is meant for low-profile installations, such as 4U cases or HTPC enclosures. Because of the overall height is almost 40mm shorter than the RVT-12025, this CPU cooler can fit in mid-tower cases with side-panel fans as well. The overall footprint is larger however, and will require a bit of finesse to install in confined areas.

There's a protect grill covering the fan, which is mounted to the finsink using soft rubber latches. We took these images with the fan installed, which is how the unit arrives, but all of our testing was conducted with a common fan.

The major trade-off between the vertical RVT-12025 and this horizontally orientated RVT-12025D is the number of heat-pipes making contact with the CPU. With a reduced rod size from 8-gauge down to 6-gauge, Kingwin was able to fit a forth heat-pipe rod into the aluminum mounting base. We'll soon see if this helped the performance against the larger gauge heat-pipe cooler.

Revolution RVT-12025D Specifications

About the company: KWI Technology Inc.

Kingwin was founded in 1992 as a manufacturer specialized in designing and manufacturing CPU Coolers and Mobile Racks, also with goals to provide our customers with the best Computer Chassis, Thermal Cooling, Liquid Cooling, and Storage Solutions. With the company's core business of Storage Solution units is still growing at a vast rate, Kingwin started looking into the PC chassis industry. To date, Kingwin has always been considered the pioneering company that revolutionized the Storage Solution Industry by bringing out different types and great storage units. The typical and traditional beige and plastic front panel design was replaced buy the excellent and more light and cooler material of the aluminum Storage Solution units. By doing this, Kingwin started growing in the industry and still is growing up to this date.

Noctua NH-U12P

Noctua has always fascinated me with their cooling solutions. They take the concept of product refinement to a new level, and often times simply tweak key areas of an existing design rather than reinventing the wheel. A perfect example of their research and development is found in the NH-U12P CPU cooler. This new product replaces their older NH-U12F model, and now features a NF-P12 cooling fan. Through the use of four heat-pipe rods configured in a "U" design, the NH-U12P borrows from the well-established performance record of many top-level coolers. Additionally, Noctua emphasises the complete experience beyond simply cooling the processor, and optimizes their products to operate with very low noise levels.

The NH-U12P continues the legacy of Noctua's classic NH-U coolers, which won over 150 awards and recommendations from leading international websites and magazines. While retaining the successful design and the well-proven SecuFirm mounting system, the newest revision has been reworked for enhanced main board compatibility and now comes with Noctua's NT-H1 pro-grade thermal compound. Fitted with the new NF-P12 premium fan, the NH-U12P brings its predecessors' much-acclaimed quiet cooling performance to a whole new level!

Noctua includes one of their NF-P12 premium fans with the NH-U12P CPU cooler. The NF-P12 has been specifically developed for applications like CPU cooling and thanks to acoustic optimizations and Noctua's SSO-bearing this fan achieves exceptionally low noise levels and long-term stability.

The Noctua NH-U12P is comprised of four heat pipe rods spanning out to eight cooling ends. The soldered joints and 36 widely-spaced aluminium cooling fins are meant to improve heat dissipation even at low fan speeds.

NH-U12P Specifications

In comparison to many of the products we've seen on our test bench in the past several months, Noctua's NH-U12P CPU cooler utilizes a contact base that is polished smooth and has no visible texture or grain.

There are several different schools of thought on the topic of best mating surface finishes. Most hardware enthusiasts and overclockers have argued the point for years, but I usually yield to science over opinion and will share more on this topic in our test methodology section.

About the company: Noctua

Noctua arises from a cooperation between the Austrian Rascom Computer distribution Ges.m.b.H and the Taiwanese Kolink International Corporation and entertains a development partnership with the Austrian Institute of Heat Transmission and Fan Technology (Österreichisches Institut für Wärmeübertragung und Ventilatorentechnik, ÖIWV). These connections form the key to the achievement of our goal: The partnership with the ÖIWV permits the application of scientific measurement instrumentation, methods of calculation and simulation technology in the R&D process. Rascom's long, customer-oriented experience in developing and distributing sound-optimised high-end products ensures a clear focus on the users' needs. The use of Kolink's advanced manufacturing technology and ultra-modern production plants allows us to efficiently implement our technical edge and provide solutions of the highest standard in quality and performance.

What does "Noctua" mean?

The little owl, Athene noctua, is the symbol of the Greek goddess Athene, who represents wisdom, science and strategy. She has a marked preference for the most clever among the Greek heroes, like Odysseus, who endure their adventures by the use of savvy consideration instead of mere force. Until today, the owl symbolises intelligence and prudence, its manlike face "emblematises" attentiveness and communication. We from Noctua follow the suit of its calm and accurate observation in the dark, its soundless flight as well as the effective, economical use of its powers and precise attack.

OCZ Vendetta 2

OCZ Completely surprised us when the original Vendetta HDT CPU cooler was tested and secured a top position among our collection of coolers. It was later discovered that the loud high-volume 92mm fan was included for a reason: the fins were much longer than the Xigmatek HDT-S963 it was loosely based off of and needed the extra push to force air past them. But OCZ didn't leave well enough alone, and recognized where there could be the potential for even more performance out of the HDT design. So back to the design table they went, and created the OCZ Vendetta 2 HPT CPU Cooler OCZTVEND2.

The OCZ Vendetta 2 is an efficient new CPU cooler that utilizes a distinctive stacked fin design and heat-pipe Direct Touch (HDT) technology. In this version of their popular cooler, OCZ designed the OCZTVEND2 to use large 8-gauge copper heat-pipe rods combined with a large low-noise fan. Together these items match to offer a perfect balance, allowing the Vendetta 2 to quietly cool even the most robust quad-core system.

Utilizing the proven performance of their original Vendetta HTD design, the Vendetta 2 has direct contact with the processor using three copper heat pipes to ensure the most rapid heat transfer and a lighter weight. OCZ's unique dimple micro-configuration of the stacked aluminum fins adds turbulence, reducing the skin effect of laminar air flow for more efficient circulation within your case.

The Vendetta 2 also offers an extra performance boost over the more compact original version. The ultra-quiet 120mm fan comes equipped with anti-vibration rubber latches to reduce excess noise, so high-volume airflow doesn't have to mean high-volume noise like the 92mm version fan.

OCZTVEND2 Specifications

• For Sockets AMD 754/755/939/AM2 and Intel LGA775
• 3 Pure Copper heat pipes for superior heat dissipation
• Pure Aluminum fins for ultimate durability
• Heatsink Dimensions:(W)120 x (H)50 x (D)159mm
• Fan Dimensions: (L)120 x (W) 120 x (H)25mm
• Rated Voltage: 12V DC
• Fan Speed: 800-1500 RPM
• Fan Air Flow: 65-81 CFM
• Noise Level: 20-32 dBA
• Bearing type: Rifle
• Connector: 4 pin with PWM
• Includes: 120mm Fan with rubber connectors
• Mounting Hardware for all above CPUs

EDITORS NOTE: Because of the fairly dense finsink system on the Vendetta 2, the stock fan (not used in this article) is best suited for noise reduction and not cooling performance. After dozens of re-tests, it's been concluded that a 72-78 CFM fan provides the optimum airflow for this cooler.

As with all HDT coolers, there are small "gutters" to each side of the heat-pipe rod. These gutters are very small, but they are still large enough to collect excess Thermal Interface Material. It's recommended that a carbon and aluminum-oxide based TIM be used with all copper surfaces. There are many excellent options tested in our 33-Way Thermal Interface Material Comparison article.

About the company: OCZ Technology

Entering the memory market in August 2000, OCZ Technology was built around the determination to manufacture the best high speed DDR and RDRAM. OCZ was founded by enthusiasts, for enthusiasts, and their commitment to the end-user has not digressed. OCZ Technology has been an innovator in many areas.

We were the first manufacturer to make Dual Channel optimized memory available to the public, which originally took advantage of nVidia's Twinbank or Dual DDR architecture, found in their nForce chipset. We have now taken that technology and tailored it for the Canterwood, and Granite Bay chipset's. OCZ developed and was the first to implement ULN technology, which has been a critical element in the manufacturing process for some time.

We at OCZ diligently work to improve communication with CPU and motherboard chipset manufacturers prior to the release of their products. Only in this manner can we fine-tune the memory's SPD settings, ensuring a synergistic relationship between the memory module, memory controller, and microprocessor. In today's rapidly evolving semiconductor industry, such communication is not simply research, but a necessary component of the manufacturing process.

Thermalright Ultra-120 eXtreme

Thermalright introduced the Ultra-120 eXtreme many months back, but it wasn't until recently that I discovered that some enthusiasts considered it better than the leading HDT solutions. In all honesty, I had never tested this cooler before now because Thermalright would claim that there were enough reviews out on the product already whenever I would request it. But now that I've discovered some overclockers giving it high praise, I had to know how well it compared.

Thermalright is secretly one of my favorite manufacturers from way back in the day. The first heat-pipe cooler I ever used was the Thermalright SI-128, and two years back it was performing so much better than the competition that everyone began using their design. Just like the saying goes: "the more things change the more they stay the same".

One of the things that I remember most about this industry is the few names that forge ahead with producing high-quality products without much marketing hype. Similar to the way Crucial packages it's system memory modules, Thermalright packages their coolers inside a plain brown box. This approach used to make me wonder if they were simply trying to save money or avoid passing on the cost of marketing to the consumer. But since neither of these companies has yet to put out a "bad" product, I think the plain brown packaging is more of a message: we don't need to dress up our products... they perform well without the hype.

Among the short list of other unchanged habits in the Thermalright factory is the absence of a factory-included cooling fan with their products. This allows the consumer to match their CPU cooler to the best fan that fits their needs, and in all actuality is probably the best option for enthusiasts (but may also be confusing for inexperienced consumers).

Of the new product changes, Thermalright has adapted a proprietary bent winglet design to minimize airflow resistancein the Ultra-120 eXtreme. I am a little skeptical of their stated intention, since streamlining will reduce resistance and bends will do exactly the opposite. But aside from the wording, this is similar in concept to OCZ's dimple micro-configuration which adds turbulence and reduces the skin effect of laminar air flow as a result.

Both sides of the Ultra-120 eXtrme are made to accomdate a 120mm cooling fan, and Thermalright has included the necessary wire retaining brackets to enable this configuration. Unlike many other manufactuers that use a "U" design with four heat-pipe rods, Thermalright makes use of six total nickel-plated copper heat-pipe rods amounting to twelve cooling ends in the circuit.

When I stop to think about it, there really aren't very many other coolers that can boast this many heat-pipes in one small unit. Even the overgrown Scythe Mugen SCINF-1000 only offered five heat-pipe rods (with ten cooler ends total), and that cooler is easily three times as large as the Ultra-120 eXtreme.

Exactly opposite of Noctua's mirror finish, the Ultra-120 eXtreme features a very uneven "freshly ground" finish. The image below is a close-up of the eXtreme's CPU mating surface, which is convex by design and meant to compensate for the irregular finish of processor Integrated Heat Spreaders. Nevertheless, the contact surface is full of crevaces and not likely to offer exceptional thermal conductivity because of the additional thermal paste which will be necessary. I'm biting my tongue for now and not going into detail, but you'll want to read through the Surface Finish Impact portion in the testing methodology section which follows.

Our test sample of the Ultra-120 eXtreme came with the redesigned mounting system, and did not require any additional washers to increase compression onto the processor. We understand that older versions were plagued with a weak mounting strength, but I assure you that this version had more than enough tension to make it difficult to completely tighten down.

About the company: Thermalright, Inc.

Thermalright is an elite design house that manufactures cooling products for computer components for the best quality and performance your money can buy. In 2002, AMD released its first generation Thunderbird CPU and since then we have been there every step of the way to counter high voltage and high heat with innovative design and highly acclaimed cooling solutions not only for AMD but for Intel as well. One of early well known solutions was the SK-6. With many positive and rave reviews under its belt Thermalright bolted to the top as the heat sink manufacturer mostly preferred by Overclockers and enthusiasts around the World.

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.

Testing Methodology

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 fan removed and replaced with our specified common test fan. 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 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 Engineer Version 4.20.1170 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 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 report to the nearest whole number. To 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.

Test System

• Motherboard: Gigabyte GA-X48T-DQ6 (Intel X48 Chipset) with version F4 BIOS
• System Memory: Corsair PC3-14400 DDR3 1800MHz
• Processor: Intel Q6600 G0 Stepping Core 2 Quad 2.4GHz (Overclocked to 3.3 GHz)
• Audio: HT Omega Claro Plus+ AD8620BR Op Amp Sound Card
• Video: Gigabyte GV-NX98X1GHI-B GeForce 9800 GX2
• Disk Drive 1: Western Digital 74GB WD740ADFD 10,000 RPM SATA
• Disk Drive 2: (Paging File) MemoRight GT MR25.2-064S 2.5-Inch 64GB SATA SSD
• Optical Drive: ASUS BC-1205PT SATA Blu-ray Disc
• Enclosure: Lian Li PC-B25B Black Aluminum Mid-Tower ATX Case
• PSU: ePower Technology EP-1200P10 xScale 1200W PSU
• Monitor: SOYO 24-Inch Widescreen LCD Monitor DYLM24D6
• Operating System: Windows XP Professional SP-2 (optimized to 16 processes at idle)

Support Equipment

• OCZ Freeze Thermal Interface Material (No curing time necessary or given)
• Noctua 120mm cooling fan, model NF-P12
• Noctua 92mm cooling fan, model NF-B9

All of our tests are conducted using two different product orientations: horizontal and vertical. So far as we can tell Benchmark Reviews is probably the first website to test with this method; but it's very likely that others will soon follow our lead. At the start of our test period, the test system is orientated sideways in a flat "desktop" position which places the motherboard and processor horizontally to face up towards the ceiling. Next, the computer system is powered on and EVEREST system stability tests are started with Stress CPU and Stress FPU options selected. Then for a minimum of ten minutes 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 CPU core levels are recorded and the first benchmark segment is complete. EVEREST remains running at full load into the next test segment.

The second benchmark segment begins by simply turning the test system vertically upright, so that the motherboard and CPU are facing to the side. Many of the products we have tested utilize a "U" pattern in the heat-pipe rods, and the upright system orientation favors this particular product design because it removes the effect of gravity on the heat-pipes' thermal cycle. For a minimum of five additional minutes EVEREST continues to load each CPU core, and once temperatures have plateaued the ending ambient room temperature and CPU core levels are recorded. This process was identical for all cooling solutions used in our benchmark tests segments.

CPU Cooler Test Results

Benchmark Reviews is still a rather new website, even though we have just proudly completed our first year on the web. So in the spirit of improving on the old ways of testing, we have decided it was time for the industry to see things from a new perspective. Beginning with this review series, Benchmark Reviews is doing two things to change the way CPU coolers are tested:

1. We will test coolers using a common fan so that air speed and volume between products do not have an impact on our results.
2. We will test coolers in both a horizontal and vertical position, since heat-pipes are effected by product orientation and gravity.

Like we mentioned at the beginning of this article, the CPU cooler must perform for itself before a fan can improve upon it. The concept behind this is that the cooler is isolated and compared, rather than the team of cooler and fan. Now obviously this will have an impact on our results, which will not match the results of other websites that use the factory included fan.

So with the test system positioned horizontally based on our new test methodology, we were a little surprised by the new benchmark results. To begin with, the Xigmatek HDT-S1283 didn't finish on top as it has consistently done in the past. The Kingwin RVT-12025 just barely edged it out based on average performance, but it was the OCZ Vendetta 2 that took the top position by a noticeable margin. The Ultra ChillTEC cooler did a good job, albeit noisy that's the to factory fan that was used (not easily interchanged for our common fan). To our disappointment the Noctua NH-U12P, Xigmatek Red Scorpion S1283, and Thermalright Ultra-120 eXtreme all averaged behind the 92mm Kingwin RVT-9225.

The fact that any of our 92mm coolers could finish near the top is a great testament to their ability, but I personally felt like the Noctua NF-B9 fan we used was a little too tame for the task. This proved to be a major factor in the poor performance of our former runner-up champion, the OCZ Vendetta. Because of the extended fins in their design, the lower-power NF-B9 fan doesn't push with the same force as the moderately loud OCZ 92mm 0.30A fan.

It was interesting to see the order of performance get shuffled by the horizontal positioning of our test system. Even more interesting was the immediate effect it had on our test results. Here is an example of the effect on performance that turning a heat-pipe CPU cooler from a vertically-standing position to the normal horizontal position will have:

In every case where the CPU cooler used a "U" shaped heat pipe rod in their design, having the unit positioned with the rods running horizontally proved to offer a cooling benefit. This was especially true for the Xigmatek Red Scorpion S1283, which had the most significant drop in temperature out of the bunch. This goes to show you that heat-pipes are in fact prone to suffer the effects of gravity in their design. Once the vapor cools and becomes liquid, it seems to have an easier time completing the thermal circuit from side to side than it does from top to bottom. So let's see how these coolers performed with the stress of gravity removed from them:

When I tested each cooler, I made certain to keep the hardware settings identical across the test platform. This would enable me to clearly compare the performance of each product under identical conditions. While the ambient room temperature did fluctuate between 20.1~20.3°C, this would not be enough to cause a noticeable impact on our test results. For the most part, the product performance in this vertical position was very close to the same order as it was horizontally. Almost all of the products dropped a few degrees, which is something you'll want to consider if you're building an HTPC that sits horizontally.

When the dust settled, our second half of the benchmark testing indicated that we have a new champion among CPU coolers: the OCZ Vendetta 2. The trusty Xigmatek HDT-S1283 from which it borrowed its design from tied for second place with the Kingwin RVT-12025 clone. Xigmatek's newly skinned Red Scorpion S1283 finished in third place for this test, with Kingwin's RVT-9225 right on it's tail (pun) with the help of three mighty large 8-gauge copper heat-pipe rods. Noctua's NH-U12P CPU cooler finished in fifth place, with the for the vertical position benchmarks, and the Thermalright Ultra-120 eXtreme was right behind it. Just like we discovered in the last test, the Kingwin RVT-12025D, OCZ Vendetta, and Zaward VIVO PCJ004 cannot keep in-step and fall well behind the other HDT cooling solutions.

Some of the bigger disappointments in our test group belonged to the gigantic Scythe Mugen SCINF-1000, which really didn't care for the modest 120mm Noctua NF-P12 cooling fan. This would explain why Scythe built this giant to accommodate four 120mm fans total, and also why it does so poorly with only one. The Thermaltake MaxOrb also shared the last place rights, but I can't pick on it too much since it's neither behemoth in size or using Heat-pipe Direct Touch technology.

EDITORS NOTE: After initially testing these products with the 120mm Noctua NF-P12 cooling fan, we later re-tested them with a few much louder and more powerful fans. The results changed across the entire test group, and those coolers with a tighter more dense fin placement (such as the Ultra 120 eXtreme, Vendetta 2, and HDT-S1283/RVT-12025) favored the most. It is impossible to randomly select one fan that best captures what the enthusiast might use since everyone likes something different, however all future tests will include results with the stock fan (whenever included) and a high-power Yate Loon D12SH-12 fan.

CPU Cooler Final Thoughts

I really enjoyed producing this article, but probably for the wrong reasons. To begin with, I want to know which product performs the best just as much as you do; maybe even more. But thanks to having so many products available to me for testing at the same time, I have the advantage of finding a winner where nobody is looking and down-grading the product everyone is so hyped about. Several times in the past year I have found myself exchanging dialog with readers who question my results because they have experienced a different result with one particular product. Plainly put: all of my testing and the subsequent benchmark results are gathered in the exact same manner on the same test system during the same benchmark period. So if you personally feel that I didn't manage to somehow test these products to your standards, you will still have to commit to the fact that they were all tested identical fashion - apples to apples.

No doubt there will be a few readers who will scoff at my results, and claim that anyone with ten minutes of experience will "lap" the processor's integrated heat spreader smooth as well as polish the CPU coolers mating surface. Sure, I concede that the bonafide overclocker with more time on his/her hands than the average hardware enthusiast will wet-sand their equipment so that they can get a few extra degrees of cooling performance. But for the other 99.99% of the consumer population, this is what you can expect from these cooling products if you want the CPU cooler to perform right out of the box. Which was why we decided to test with a moderate-output fan, because we believe you'll want a product that works well without the need for a gail-force fan attached to it.

There are numerous ways to improve upon the performance that any one of these products has offered, so claiming that "if you do this or that" to one product will not exactly put it ahead of another. Take for example the Thermalright Ultra-120 eXtreme: most enthusiast like to modify this product by lapping the surface and adding additional mounting pressure by using a washer. But to that same (unecessary) extent, you could file and polish the mating surface of any one of the Heat-pipe Direct Touch coolers and use bolt-on backplate mounting to exert the same benefit. Either way you look at it, you'll have to compare stock-for-stock or modified against modified; just like anything else.

Benchmark Reviews plans to make this round-up testing a quarterly event, which will showcase the newest CPU cooling solutions for that period and test them against the previously top-ranked products. Since this is the first article in what I hope will become a long series of comparisons to come, we have decided to handle achievment awards a little differently. In each quarterly article, only the best performing and runner-up products will receive recognition for excellence. At the end of the year, we will test the entire group of best-performing CPU cooler products to nominate our "Flame of Glory" Editor Choice Award.

OCZ Vendetta 2 Conclusion

For the first three months (Q1) of 2008, one product stood out among the crowd and outperformed every other test product: the OCZ Vendetta 2 Heat-pipe Direct Touch 120mm CPU cooler.

The OCZ Vendetta 2 was very easy to install since it uses the standard pin-style compression clips. I have noticed that both the original Vendetta and the new Vendetta 2 both have a clip system that requires more force to secure than an OEM Intel cooler. This gives the Vendetta 2 a much stronger mount to the CPU in return. Although the Vendetta 2 is designed from the Xigmatek HDT-S1283 concept, there are several key differences separating the two products. Presently the OCZ Vendetta 2 CPU cooler is just reaching retail shelves, and NewEgg is listing the OCZTVEND2 for $49.99. Once this product makes it to the more popular retailers, the initial roll-out price should level out over time.

Editors Note: The stock fan was not used to test the Vendetta 2; all coolers received the same Nf-P12 fan for this article. Benchmark Reviews has determined that many enthusiasts overlooked the portions of this article which mention the use of a common fan. We have discovered that our results are significantly better than the results produced using the included stock fan. All future tests will include results with the stock fan (whenever included) and a high-power Yate Loon D12SH-12 fan. Please do not compare your results to the results we have received without first noting the equipment used in the 'Test Methodology' section of this article.

Ratings:

• Presentation: 9.00
• Appearance: 9.50
• Construction: 9.50
• Functionality: 10.0
• Value: 9.00

Final Score: 9.4 out of 10.

Excellence Achievement: Benchmark Reviews Golden Tachometer Award.

Kingwin RVT-12025 Conclusion

Additionally, the Kingwin Revolution RVT-12025 HDT cooler performed nearly just as well as the Vendetta 2 and secures a solid second place in our benchmark results.

Kingwin's RVT-12025 is a clone of Xigmatek's HDT-S1283 cooler, which has already won our Golden Tachometer Award. If it weren't so difficult to find Xigmatek coolers in North America, there might not have ever been a reason to duplicate the design. But because Kingwin can offer their readily-available inventory to the US and Canada, the Revolution RVT-12025 will prove to be a hot item. Presently NewEgg offers the RVT-12025 for $31.99, which is considerably less expensive than some of the other cooling solutions tested in this article.

Editors Note: The stock fan was not used to test the RVT-12025; all coolers received the same Nf-P12 fan for this article. Benchmark Reviews has determined that many enthusiasts overlooked the portions of this article which mention the use of a common fan. We have discovered that our results are significantly better than the results produced using the included stock fan. All future tests will include results with the stock fan (whenever included) and a high-power Yate Loon D12SH-12 fan. Please do not compare your results to the results we have received without first noting the equipment used in the 'Test Methodology' section of this article.

Ratings:

• Presentation: 9.25
• Appearance: 9.00
• Construction: 9.50
• Functionality: 9.75
• Value: 9.50

Final Score: 9.4 out of 10.

Quality Recognition: Benchmark Reviews Silver Tachometer Award.

Questions? Comments? Benchmark Reviews really wants your feedback. We invite you to leave your remarks in our Discussion Forum.

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