Original Link: http://www.anandtech.com/show/7738/closed-loop-aio-liquid-coolers



Remember the time when liquid cooling a computer chip was considered to be an extreme approach, one performed by hardcore enthusiasts and overclockers alone? Everything had to be personally designed and or procured by the user, as there were no specialized commercial products available at the time. Radiators were modified heater cores extracted from cars, CPU blocks were rare and occasionally machined at local workshops using a copper block and a lathe, while high-performance tubing came from shops with medical supplies.

As demand grew, aided by the ever-increasing noise of small CPU heatsinks, companies specializing on liquid cooling solutions began turning up -- a little too fast perhaps, as tens of companies were founded within a few months' time and very few of them actually survived for more than a couple of years. Enthusiasts could then buy specialized liquid cooling equipment and even whole kits from just one seller and only had to assemble the setup into their system. That of course is no simple process for an amateur and a nightmare for a system builder, who cannot ship a system with a topped off water cooling tank or assume that the user has the skills required to maintain such a system, therefore the potential market remained limited to advanced users only.

This all changed in 2012, when Asetek came up with an inexpensive closed loop solution, a liquid cooling device that was leak-free and required no maintenance at all. The radiators of the first few solutions were small and their overall performance hardly better than that of air coolers; however, aided by the modernization of computer cases, the mounting of larger, thicker radiators inside a PC soon was not a problem. In many cases the kits were now no harder to install than any CPU cooler and required no maintenance at all, opening the market to virtually every computer user seeking a performance cooling solution. This spurred massive interest amongst OEMs and manufacturers, who all strive for a slice of the pie.

There have been tens of AIO (All-in-One) closed loop liquid coolers released just in 2013; today, we are having a roundup with 14 of them, coming from five different manufacturers, alphabetically listed in the table below.

Product Radiator Effective Surface Radiator Thickness # of Fans (Supplied / Maximum) Speed Range of Supplied Fans (RPM) Current Retail Pricing
Cooler Master Seidon 120V 120mm × 120mm 27mm 1 / 2 600-2400 $49.99
Cooler Master Nepton 140XL 140mm × 140mm 38mm 2 / 2 800-2000 $99.99
Cooler Master Nepton 280L 140mm × 280mm 30mm 2 / 4 800-2000 $119.99
Corsair H75 120mm × 120mm 25mm 2 / 2 800-2000 $69.99
Corsair H90 140mm × 140mm 27mm 1 / 2 600-1500 $84.99
Corsair H100i 120mm × 240mm 27mm 2 / 4 800-2700 $109.99
Corsair H105 120mm × 240mm 38mm 2 / 4 800- 2700 $119.99
Corsair H110 140mm × 280mm 29mm 2 / 4 600-1500 $126.99
Enermax Liqmax 120S 120mm × 120mm 32mm 1 / 2 600-1300
600-2000
600-2500
(Multi-range)
$163.00*
Enermax Liqtech 120X 120mm × 120mm 43mm 2 / 2 600-1300
600-2000
600-2500
(Multi-range)
$171.10*
NZXT Kraken X40 140mm × 140mm 27mm 1 / 2 800-2000 $89.99
NZXT Kraken X60 140mm × 280mm 27mm 2 / 4 800-2000 $119.99
Silverstone Tundra TD02 120mm × 240mm 45mm 2 / 4 1500-2500 $118.99
Silverstone Tundra TD03 120mm × 120mm 45mm 2 / 2 1500-2500 $97.99

*The coolers from Enermax are not widely available in the USA at the time of this review, with the only viable option appearing to be that of import from Asia or Europe.

Although Asetek was the first to come up with the design and they hold patents for it, they are not the only OEM of AIO cooling solutions today. At least three different OEMs are behind the kits listed in the table above. We will have a closer look at each one of them in the following pages.



Cooler Master

Cooler Master is a company with a tradition of cooling-related products and thus it is no wonder that they jumped into the AIO liquid coolers wagon almost instantly. They have a healthy selection of products and decided to ship us their two Nepton series coolers, their most popular series at this point in time, along with the Seidon 120V, a very low cost, entry level solution.

Cooler Master Seidon 120V

The Cooler Master Seidon 120V is the smallest, simplest and least expensive AIO cooler of this review. The packaging reflects that, being a relatively simple brown cardboard box, unlike any other in this particular roundup. Looks aside, the packaging is well designed, full of information on the cooler, and the cooler is very well protected inside the cardboard packaging.

Inside the box, the user will find a leaflet with installation instructions, the necessary mounting hardware, and a syringe with thermal compound. Also included is a single 120mm fan with a wide speed range of 600 to 2400 RPM; it is an all-black model with wavy blades.

Both technically and aesthetically, the Cooler Master Seidon 120V is a rather simple design. The 27mm thick, 120mm wide radiator is the smallest and least expensive design available today. Wavy aluminum fins are formed between the liquid pass-through channels, which are not dense but not sparse either. There are imperfections in the fins but these are to be expected with a low-cost radiator.

The square block-pump assembly is entirely made out of plastic, which is not bad in terms of durability but gives a feeling of cheapness. The company logo is etched on the top of the block and a bright blue LED turns on when the pump is powered on. Only the base of the block is made out of copper, which is expected given the price. This copper base has been attached to the rest of the assembly with the aid of ten triangular screws and has a smooth, well-machined surface, although it has not been machined down to a mirror finish. The tubing is corrugated and a little hard to bend but at least the fixing points on the CPU block assembly are rotatable sideways.

Cooler Master Nepton 140XL

Unlike the basic 120V, the Nepton 140XL is a significantly more sophisticated, detailed product. It does however cost twice as much as the 120V. It comes supplied in a carefully designed black-purple cardboard box, well protected inside cardboard packaging.

The bundle is not much different than above, limited to the necessary mounting hardware, a leaflet with installation instructions, and a syringe of thermal compound; a Y-splitter for the attachment of two fans onto one header is also included. Two powerful 140mm fans come with the cooler, with a speed range of 800 to 2000 RPM. These "Jetflo" fans are supposed to have high static pressure and the rubber pads absorb vibrations, reducing noise.

Visually, the Nepton 140XL is not much different from the Seidon 120V. Technically, the two coolers are nothing alike. The 140mm radiator of the Nepton 140XL is not only wider but is also 38mm deep, increasing the effective heat dissipation surface by well over 50%. Size aside, the design of the radiator is similar, with wavy aluminum fins between the heat exchanging channels and with a frame offering the ability to mount either 120mm or 140mm fans on it. However, it would seem that manufacturing imperfections are still present, with several of the fins significantly deformed. It appears as if the radiator was struck with something, deforming half a channel of fins, yet we received the packaging in excellent condition and this side of the radiator was facing inwards, towards the center of the packaging. Quality control issues in Cooler Master's manufacturing paradise are the only reasonable guess we can make -- that or the cooler was previously tested and repackaged for our review, though that seems unlikely.

The square block-pump assembly is once again entirely made out of plastic. Even though it looks much better and of higher quality than that of the 120V, plastic rarely is the way to go when you want a worthwhile aesthetic outcome. The company logo is etched on the top of the block and is surrounded by a frame with a white LED, which turns on when the pump is powered up. A plastic frame is sandwiched between the cap and the base of the assembly, with holes for the mounting of the installation brackets. The copper base of the assembly is smooth but not machined perfectly; although they cannot be felt by touch, the sandpaper grooves are clearly visible with a naked eye.

Cooler Master Nepton 280L

The Nepton 280L is Cooler Master's heavy artillery. We received it supplied inside a well-designed cardboard packaging with a black/purple color theme, visually very similar to that of the 140XL. The main attraction of the kit, the large 280mm radiator, dominates the theme of the box. Inside the box, with the exception of a slightly different installation instructions leaflet, we found the exact same bundle as that of the 140XL, including two of the same 140mm "Jetflo" fans.

The Cooler Master Nepton 280L might appear like an oversized version of the 140XL but it really is not. They do share many similarities but the main part of the kit, the radiator, is very different. The radiator of the 280L, as the name suggests, is 140mm wide and 280mm long, with room for up to four 140mm fans. The frame also offers support for 120mm fans, if the user would like to use 120mm fans instead for whatever reason. However, the radiator of the 280L is only 30mm thick, which is about 25% less than that of the 140XL. Therefore, although the heat dissipation surface is greater, it is not actually double that of the 140XL. Once again, minor deformations of the aluminum fins can be seen, although not nearly as many or as serious as those we encountered on the 140XL.

The square block-pump assembly is entirely identical to that used by the 140XL as well. It features the exact same size, mounting mechanism, pump, core and everything else. The same white LED lighting frame at the top of the block has also been installed. Unfortunately, the same mediocre copper base is also present, which could use a little bit better polishing for a product of this league and price range.



Corsair

When we mentioned the word's "liquid coolers" and "roundup" to Corsair, they got a bit overexcited and shipped us five of their AIO coolers. For some reason, Corsair is extremely interested in AIO liquid coolers, which is also reflected by the fact that they are the only company that offers nine such products at this point in time, while most manufacturers are currently limited to just two or three coolers.

Corsair H75

Despite its "small" number, the H75 actually is one of Corsair's most recent designs. We received it supplied in a serious looking, black cardboard box with a blue visual theme. Inside the box, the cooler is protected by cardboard packaging.

Corsair kept the bundle of the H75 down to the very basics: a leaflet with installation instructions and the hardware required for the mounting of the cooler. The bundle is well presented though, with each type of screws/nuts inside a separate nylon bag. Two 120mm fans with grey wide blades are also included in the packaging. The fans have an operating range between 800 and 2000 RPM, which is not very high for wide-bladed 120mm fans.

The Corsair H75 is not a work of art but it does stand out visually. It features a rather small radiator that is only 120mm wide and 25mm deep, which offers no more heat dissipation surface than the radiator of the ultra-cheap Seidon 120V. Even though the radiator is of the same design, this time the aluminum fins are virtually free of imperfections, with very few slight deformations visible. The small size of the radiator gives the H75 an advantage in tight spaces but will certainly have an impact on its overall performance. Corsair also went with kink-resistant, smooth black rubber tubing of normal width, rather than the corrugated tubing many other manufacturers are using.

The block-pump assembly is round, with a silver ring on top and the company logo painted right in the middle of the cap. It also comes with the retention bracket for Intel CPUs preinstalled. The assembly is held together by no less than 20 screws, 12 for the plastic frames and 8 for the copper base. Thermal compound has been applied on the base from the factory. After our testing, we cleaned the base of the cooler, revealing a well-machined and polished surface.

Corsair H105

Announced at this year's CES, the Hydro H105 is Corsair's most recent product. It comes in a large cardboard box similar to that of the H75, yet with a red colored theme, which is the signature of Corsair's "extreme performance" products. The bundle of the H105 is almost identical to that of the H75 as well. Inside the box, we find a leaflet with the installation instructions and the necessary mounting hardware categorized inside nylon bags. However, we also found two colored rings for the CPU block. Finally, even though the wide grey bladed fans are visually similar to those included with the H75, they actually are not similar at all. The SP120L fans supplied with the H105 are much more powerful, with an operational range of 800 to 2700 RPM.

Even though the H105 looks like an oversized version of the H75, there is more to it than first meets the eye. To begin with, the radiator is not only twice as long as that of the H75 but nearly 40% thicker as well, increasing the effective heat dissipation area by well over 150%. Some minor deformations of the aluminum fins are visible this time as well; apparently, the making of such radiators is not an easy process. Although the 120mm width of the radiator makes the H105 compatible with more cases and systems, the length could become a problem, so be especially careful with that.

Similar to the H75, the block-pump assembly is round, with a silver ring on top. The silver ring however is removable and replaceable with either a red or blue ring, now included in the packaging. In addition, the company logo is not painted; on the contrary, it has been left unpainted on purpose and a white LED has been placed beneath it. The bracket for installation on Intel CPUs is once again preinstalled and the cooler has thermal compound applied on its base from the factory floor. Once again, the copper base is well machined and polished, free of imperfections.



Corsair H90

Corsair's Hydro H90 is sort of a bigger brother to the H75. It is the only AIO cooler from Corsair in this roundup that comes in silver packaging, as for some reason the company did not use its usual black-based color theme; most likely because of the all-black color of the cooler itself. Although the bundle is limited to the basics, a manual with installation instructions and the installation-related hardware that is, it is interesting to note that everything, down to the last screw, is black. The included 140mm fan is black as well and is a model with narrow blades and relatively low operating speeds, ranging from 600 to 1500 RPM.

Black, black and more black; these words can easily describe the H90. The radiator is a wider version of the same radiator used by the H75, built for 140mm fans instead of 120mm. Nevertheless, that's over 25% more heat dissipation surface, giving the H90 a significant advantage. The radiator appears well made, yet fin deformations can be easily spotted, therefore it is far from perfect. Smooth, rubber and kink-resistant tubing is used; Corsair does not appear fond of corrugated tubing.

The pump-block assembly is round and very simple. Corsair's logo has been printed on the top of the assembly and there is no lighting or anything else worthy of discussion about this block. It apparently is the simplest design that the OEM (Asetek) offers. Thermal compound is again pre-applied on the copper base of the cooler.

Corsair H110

The Hydro H110 is the largest AIO liquid cooler that Corsair currently offers. It comes supplied inside a black cardboard box with a red theme, marking it as one of Corsair's "extreme performance" products. The H110 shares the same bundle as the H90. Inside the box there is a manual with installation instructions, all-black mounting hardware that is supplied categorized inside separate nylon bags, plus two black 140mm fans, also identical to the fan supplied with the H90.

On first sight, it becomes apparent that the H110 is little more than an oversized version of the H90. The radiator has the same thickness but twice the length, allowing for the installation of two 140mm fans on each side, so up to four 140mm fans total in a push-pull configuration. Despite the relatively thin 29mm thickness, the 140mm × 280mm radiator is hefty and will not fit inside many cases, which is the most significant disadvantage of the H110. The rubber tubing is only about 30cm long, which is enough if the radiator is to be installed at the top of a case but not long enough to reach virtually any other viable position. In short, this is a cooler that will need to be matched to a limited case selection.

The same simple round pump-block assembly as that of the H75 is used on the H110 as well. Aesthetics aside, as there is nothing really left to discuss about that, we found it strange that such a small ceramic pump can create a pressure significant enough to cope with the flow resistance of such a large radiator. It is highly likely that the performance of the whole setup will be limited by the low power of the pump. Thermal compound has once again been pre-applied on the copper base of the cooler.

Corsair H100i

Although it is not the most powerful AIO cooler that Corsair currently offers, the H100i is their pride and joy, therefore it could not be missing from this review. As every other AIO cooler rated as an "extreme performance" product, Corsair supplies the H100i in a black cardboard box with a red color theme. The bundle of the H100i might appeare a little richer than most, but it's not. Aside from the manual with the installation instructions and the mounting hardware, there are the cables required for the use of the cooler and a small advertising leaflet with Corsair's latest products; nothing of particular note. Two 120mm fans with wide grey blades are included, the same fans supplied with the H105 to be exact, which have a speed range of 800 to 2700 RPM.

Out of all Corsair's AIO cooling solutions in this review, the H100i is the one that really stands out. Unlike any of the previous Hydro models discussed in this review, the H100i is not made by Asetek; CoolIT is the OEM behind it. The 120mm x 240mm radiator is similar to that of the H105 but considerably thinner, at only 27mm deep. It is of almost identical design, with wavy aluminum fins soldered on the liquid pass-through channels; however, although it might only be a coincidence, we should note that the number of deformations/imperfections of the fins is notably lower.

The block-pump assembly is rectangular, with a shiny, highly reflective black top cover. The company logo lights up once the pump is powered on. On the side of the assembly, there are connectors for the fans and the USB interface of the system; this model is compatible with Corsair's Link software, allowing almost complete control via software. We should note that the power connector of the pump is not the usual 3-pin fan header connector but a SATA connector instead, as the assembly needs to power up to four fans, the pump, and all of the electronics of the interface as well. Thermal compound has been pre-applied to the copper base of the assembly, which is very smooth and polished down to a mirror finish (the grainy appearance of the block in the picture is actually due to reflections from the environment).



Enermax

Enermax gained popularity and reputation through their high quality power supply units. The company has been around for decades but has only more recenty begun diversifying into cases and cooling solutions. They have also added a couple of new AIO liquid coolers into their product range and they shipped us two of them for this review. Unfortunately, these coolers are not yet available in the North American region.

Enermax Liqmax 120S

The first AIO liquid cooler from Enermax is the Liqmax 120S. The Liqmax series consists of two products, which are essentially the same cooler but with a different fan. Both models are depicted on the box. We received the LM120S-HP model, and the fan of lacks LED lighting on this model.

Even though the bundle of the Liqmax 120S is nothing special, it comes well presented, with the mounting hardware packed in separate nylon bags. There also is a manual with installation instructions and a syringe with thermal compound included. The biggest attraction of this kit however is definitely the fan. Although it looks like a simple, black fan without lighting or any notable features, there is a switch on the fan's engine that adjusts the speed range of the fan. There are three settings: 600 to 1300 RPM, 600 to 2000 RPM and 600 to 2500 RPM. By default, the fan is set on the 600 to 2000 RPM range.

Visually, the Liqmax 120S is not much different from most other AIO coolers with 120mm wide radiators. The radiator, measuring 32mm deep, is slightly thicker than the one used by the Seidon 120V and the Corsair H75. There are almost no deformations or imperfections about the aluminum fins, although a couple of them are slightly bent. Enermax went with black corrugated tubing, which is durable but a bit of a pain to turn. At least the connections on the block can turn sideways, relieving some of the stress.

The block-pump assembly is entirely made of plastic, with the exception of the copper base of course. Although plastic makes such designs look cheap, Enermax tried to improve the appearance of their product by engraving a symmetric pattern on it, grooves on its sides, and added blue LED lighting beneath their company logo in the middle of the block. It does help but the block of the 120S is definitely not the best looking around. The copper base of the block however is very well made, smooth and machined down to a nearly perfect finish.

Enermax Liqtech 120X

Despite the name, not Liqmax but Liqtech is actually the best series of Enermax's AIO cooling solutions. There are two versions with different radiators, the 120X and the 240. We received the small version, the 120X, supplied in a very well designed black/red cardboard box.

The bundle of the Liqtech 120X consists of the standard items; a manual with installation instructions, mounting hardware, and a syringe with thermal compound. Enermax also supplies a 3-pin Y-splitter fan cable, which can be used to power two fans off a single header. Two 120mm fans are supplied with the Liqtech 120X, both being the same as the black range-adjustable ELC-LT120HP fan of the Liqmax 120S kit.

If this were a beauty contest, the Liqtech 120X would be the most serious contestant. Enermax definitely spent a lot of time and energy designing the 120X so as to stand out from the crowd. The radiator has grooved aluminum blocks attached to its sides, with the company logo printed on them. Anti-vibration material forms red stripes where the fans will be seated. The design of the radiator itself is very different from that of most other kits as well; instead of wavy aluminum fins between the liquid pass-through channels, this design forms single, "seamless" fins from one side to the other. It is considerably thicker as well, measuring 43mm deep, which can be a problem in some system cases.

The block-pump assembly is entirely metallic as well, with an aluminum frame and a copper base. The black aluminum top of the block forms fins, which sort of function as a small heatsink, with the company name and logo clearly visible in silver. Even the mounting supports are made out of solid aluminum, with those for installation on an Intel CPU already attached to the block. The copper base is clean, smooth and very well machined. This AIO cooler obviously is a very different design than those from Asetek and or CoolIT; Enermax however did not want to reveal their source.



NZXT

NZXT is another company that recently decided to jump on the AIO cooling bandwagon and they did so a little bit furiously. Instead of releasing a wide selection of products, NZXT released only two coolers, both meant for 140mm fans alone, clearly aiming for the high-performance segments of the AIO coolers market. They supplied us with both of their AIO coolers for this review.

NZXT Kraken X40

We received the Kraken X40 in a well-designed, white box with plenty of information about the product printed on its back and sides. Inside the box, the cooler is protected by cardboard packaging and nylon bags. The bundle of the Kraken X40 comes well presented, with the mounting hardware categorized into separate nylon bags. All of the mounting hardware and brackets are black. There also is a leaflet with installation instructions and a CD with the Kraken Control software, a rather simple piece of software that can be used to control the speed of the pump, fans, and the lighting of the CPU block. A single 140mm fan with a black frame and white blades is supplied with the X40. The fan has a very wide speed range of 800 to 2000 RPM and a fluid bearing for high performance and reliability.

Aesthetically, the Kraken X40 is hardly any different from most other Asetek designs. NZXT went with the normal thickness (27mm) on a 140mm wide radiator, most likely to ensure the compatibility of the cooler with most of their cases. The radiator follows the standard design of every other Asetek-made AIO cooler to this date, with wavy aluminum heat dissipation fins soldered on to the liquid pass-through channels. Unfortunately, fin deformations and imperfections are once again common. NZXT is using black, kink resistant tubing made of hard, smooth rubber. It is noteworthy to mention that the Kraken X40 has 16" (40cm) long tubing, which is about 4" (10cm) longer than that in most other kits.

The circular block-pump assembly does look like the standard Asetek designs, such as the ones of the Corsair H90/H110 kits, yet there is more to it than first meets the eye. There are many wires coming in and out of the block; one is a 3-pin header for power, one is for the USB interface, and the third is for the connection of up to two fans. If the fans are to be controlled via NZXT's Kraken Control software, they need to be connected to the block. NZXT is confident that all of these can be powered via a single 3-pin fan header. At the top of the block, covered by a sticker that is a pain to remove, a circular ring with NZXT's logo on the side can be seen. There is not one but several LED lights beneath it, allowing full control of its lighting color via the supplied software. It is also possible to adjust the color according to the temperature. However, the pump will not light up until it receives a command from the software, so do not get concerned if there is no lighting when you first start up your system.

NZXT Kraken X60

The Kraken X60 essentially is the bigger brother of the X40. It comes supplied in a similarly designed cardboard box, just a little bit larger and with thicker packaging material inside. The bundle is virtually identical, with the same black mounting hardware and a similar manual with installation instructions. However, two 140mm fans are now supplied with the cooler, the same 140mm fans with the black frame and white blades as the one supplied with the X40.

Essentially, the Kraken X60 is both technically and visually identical to the X40, with the exception of the radiator, which is twice as long. The 280mm long radiator can now support up to four 140mm fans, with two supplied by NZXT. Other than that, it has the exact same width and thickness as the radiator of the X40, as well as the same issues with the quality of the heat dissipation fins.

The block-pump assembly is very similar to that of the X40 as well, featuring the same circular design and the same multi-color LED lighting. There are differences on the wiring though, as the assembly now requires power from a SATA connector and can be used to control up to four fans. It appears that the pump is still being powered by the 3-pin header, allowing the control of its speed by the motherboard, with the SATA connector reserved for powering the USB interface and the fans. Thermal compound has been pre-applied on the copper base of the cooler, which is machined to a nearly perfect finish.



Silverstone

Silverstone is another well-known name amongst advanced users and enthusiasts. The company earned their reputation from their first PSUs and original case designs and soon diversified towards cooling related products. They currently offer just two AIO liquid cooling solutions, the Tundra series. The company shipped both of them to us for this review.

Silverstone Tundra TD02

Silverstone ships the Tundra TD02 inside a large cardboard box with a black/blue theme. The box has plenty of pictures and information about the cooler printed on all of its sides. The company also supplies a fairly standard bundle with the Tundra TD02, which consists of a manual with installation instructions, mounting hardware and a syringe with thermal compound. There also is a 3-pin Y-splitter fan cable included, which can be used to power two fans off a single header. Silverstone supplies two 120mm fans with the TD02. The fans have back frames and curved, notched white blades that supposedly reduce aerodynamic noise, as well as fluid-state bearings for prolonged life. Their speed range is rather narrow, ranging from 1500 to 2500 RPM.

Visually, the Silverstone Tundra TD02 certainly stands out a lot. Although it is somewhat different, the Tundra TD02 could be coming from the same OEM that makes the Enermax Liqtech 120X as well; however, Silverstone did not want to reveal their source. The very large and deep radiator with the grey aluminum frame stands out, the size of which overwhelms any Asetek/CoolIT design. Size is not always a good thing though, as the 45mm thick design could bring serious compatibility issues, especially if the case has been designed with 27-29mm radiators in mind.

The design of the radiator is quite different from that of most other kits. Like the radiator of the Liqtech 120X, instead of wavy aluminum fins between the liquid pass-through channels, this design forms single, "seamless" fins from one side to the other, which are soldered onto the channels. The design of the fins and the overall size of the radiator though is different.

The block-pump assembly of the Tundra TD02 stands out over that of most other kits as well. It is entirely metallic, made of nickel-plated aluminum with a copper base. A badge with Silverstone's logo lies in the middle of the aluminum cap, which also has very subtle blue LEDs surrounding it. There is something unique about this block however; unlike any other assembly, including that of the Liqtech 120X, the copper base of the block is not attached to the assembly with screws, leaving the bottom of the block entirely plain. It has also been machined down to a perfect, smooth finish. The only thing that we could complain about is the use of narrow, stiff, white corrugated tubing, which is beneath the quality of such a product.

Silverstone Tundra TD03

Confusing as this may be, the Tundra TD03 actually is a smaller version of the TD02. It comes in a similarly designed cardboard box with a black/blue color theme, only it's significantly smaller. Despite the change in size however, the cooler remains very well protected within cardboard packaging and inside nylon bags. It also shares exactly the same bundle with the TD02, including the manual with the installation instructions. The two 120mm fans supplies are the same as those of the TD02, with a black frame and curved, notched white blades.

Both visually and practically, the Tundra TD03 is just a shorter version of the TD02. The radiator also shares the same design, and is just as wide and thick as the radiator of the TD02, yet nearly half as long, which means that it essentially has half the heat dissipation surface. Nevertheless, Silverstone still supplies two 120mm fans, to be used in a push-pull configuration. It is interesting to note that this radiator design appears a lot more solid, without any imperfections or bent fins, which appear to be very common on radiators with wavy aluminum fins.

As expected, the fully metallic block-pump assembly of the Tundra TD03 is identical to that of the TD02. The top and frame of the assembly are made out of nickel-plated aluminum, with the base of the block made out of solid copper. Even the mounting braces are made of solid aluminum, with those meant for Intel CPUs preinstalled on the block from the factory. Once again, the copper base is not attached to the aluminum frame with screws, at least not screws visible from the bottom of the assembly, leaving the base of the cooler perfectly clean and smooth.



Testing Methodology

Although the testing of a cooler appears to be a simple task, that could not be much further from the truth. Proper thermal testing cannot be performed with a cooler mounted on a single chip, for multiple reasons. Some of these reasons include the instability of the thermal load and the inability to fully control and/or monitor it, as well as the inaccuracy of the chip-integrated sensors. It is also impossible to compare results taken on different chips, let alone entirely different systems, which is a great problem when testing computer coolers, as the hardware changes every several months. Finally, testing a cooler on a typical system prevents the tester from assessing the most vital characteristic of a cooler, its absolute thermal resistance.

The absolute thermal resistance defines the absolute performance of a heatsink by indicating the temperature rise per unit of power, in our case in degrees Celsius per Watt (°C/W). In layman's terms, if the thermal resistance of a heatsink is known, the user can assess the highest possible temperature rise of a chip over ambient by simply multiplying the maximum thermal design power (TDP) rating of the chip with it. Extracting the absolute thermal resistance of a cooler however is no simple task, as the load has to be perfectly even, with the ability to vary the load, as the thermal resistance also varies depending on the magnitude of the thermal load. Therefore, even if it were possible to assess the thermal resistance of a cooler while it is mounted on a working chip, it would not suffice, as a large change of the thermal load can yield very different results.

Appropriate thermal testing requires the creation of a proper testing station and the use of laboratory-grade equipment. Therefore, we created a thermal testing platform with a fully controllable thermal energy source that may be used to test any kind of cooler, regardless of its design or compatibility. The thermal cartridge inside the core of our testing station can have its power adjusted between 60W and 340W, in 2W increments (and it never throttles). Furthermore, monitoring and logging of the testing process via software minimizes the possibility of human errors during testing. A multifunction data acquisition module (DAQ) is responsible for the automatic or the manual control of the testing equipment, the acquisition of the ambient and in-core temperatures via PT100 sensors, the logging of the test results, and the mathematical extraction of performance figures.

Finally, as noise measurements are a bit tricky, we're measuring these manually. Fans can have significant variations in speed from their rated values, thus their actual speed during the thermal testing is acquired via a laser tachometer. The fans (and pumps, when applicable) are powered via an adjustable, fanless desktop DC power supply and noise measurements are being taken 1m away from the cooler, in a straight line ahead from its fan engine. At this point we should also note that the decibel scale is logarithmic, which means that roughly every 3 dB(A) the sound pressure doubles. Therefore, the difference of sound pressure between 30 dB(A) and 60 dB(A) is not "twice as much" but nearly a thousand times greater. The table below should help you cross-reference our test results with real-life situations.

Noise Level Reference Values
<35dB(A) Virtually inaudible
35-38dB(A) Very quiet (whisper)
38-40dB(A) Quiet (slight humming)
40-44dB(A) Normal (humming noise, comfortable level)
44-47dB(A) Loud* (strong aerodynamic noise)
47-50dB(A) Very loud (strong whining noise)
50-54dB(A) Extremely loud (level equivalent to a ≈1500W vacuum cleaner)
>54dB(A) * Intolerable for home/office use; special applications only.

* Noise levels above this are not suggested for daily use



Testing Results, Maximum Fan Speed (12V)

Fan Speed (12 Volts)

Noise level

Core temperature (60 W Load)

Core temperature (100 W Load)

Core temperature (150 W Load)

Core temperature (200 W Load)

Core temperature (250 W Load)

Core temperature (340 W Load)

Average thermal resistance, 60 W to 340 W

The above charts depict exactly why a user needs to be more than just a little careful when selecting a cooler. Even though they appear similar and some of them even nearly identical, the performance of each and every AIO cooler that we have tested varies greatly. For instance, Cooler Master obviously sought to provide the best heavy-load performance possible and they did manage to reach the top of our charts; however, the noise of the fans that Cooler Master supplied at maximum speed is intolerable for daily use by any standards.

To give you a rough estimate, 56 dB(A) represents about the same level of sound as a typical box fan the same distance. The Nepton 280L is closely followed by the NZXT Kraken X60 and then the Corsair H110, both of which share about the same size and design but not nearly the same noise levels. The NZXT Kraken X60 is over 5 dB(A) quieter than the Nepton 280L, a very perceptible difference, while the Corsair H110 generates only 41.3 dB(A), which is equivalent to a soft humming noise and fairly comfortable for daily use.

Naturally, the performance decreases as we move to AIO coolers with smaller radiators, with the Corsair H100i leading the coolers using 120mm fans but its stock fans run at 2600 RPM, generating high noise levels. The Enermax Liqtech 120X and Silverstone Tundra TD03 and their beefy radiators deliver great thermal performance when compared to other single-fan AIO coolers, although Enermax proved that they could offer roughly the same performance with just one fan and much lower noise levels, making Silverstone's choice to include two fans appear somewhat redundant.

Under a low thermal load however, the charts shift greatly. As the thermal load is much lower, the low temperature dissipation efficiency of the cooler now matters a lot more than its maximum thermal load capacity. Corsair's H100i offers the best thermal performance, outperforming coolers with significantly larger radiators, including Corsair's own H110, closely followed by another 240mm long cooler, the Silverstone Tundra TD02. The gap between the budget-level and high-performance products now closes, with the Corsair H75 being the most notable example, as it manages to outperform its own larger version, the H105. Apparently, bigger is not always better and the lower flow resistance of the single fan radiator gives the Corsair H75 a faster energy transfer rate at lower temperature deltas.



Testing Results, Low Fan Speed (7V)

Fan Speed (7 Volts)

Noise level

Core temperature (60 W Load)

Core temperature (100 W Load)

Core temperature (150 W Load)

Core temperature (200 W Load)

Core temperature (250 W Load)

Core temperature (340 W Load)

Average thermal resistance, 60 W to 340 W

After dropping the voltage of the fans down to 7V, the characteristic performance of several AIO coolers changes quite a bit. As expected, the performance gap between most single and dual fan radiator models widens, as the larger surface maintains a greater heat dissipation rate as the flow rate decreases. The charts are once again led by Cooler Master's Nepton coolers, although that hardly qualifies as "low noise testing" as both coolers still generate high noise levels and are most definitely unsuitable for a low noise environment.

Corsair's H110 displays tremendous thermal performance under very heavy load, in conjunction with very low noise levels. NZXT's Kraken X60 delivers about the same thermal performance, which was to be expected as it virtually is the same design, yet the noise levels are significantly higher; apparently, Corsair chose their fans a bit more wisely (or they just got lucky). Silverstone's Tundra TD02 also fares considerably better this time, rivaling the high load thermal performance of all other 240mm coolers at considerably lower noise levels. Under low thermal loads, the Tundra TD02 manages to outperform most of the dual 120mm and 140mm coolers. Apparently, the large and thick radiator of the TD02 allows it to maintain high performance figures even when the airflow is reduced.

Those who are interested only in noiseless operation and are looking at AIO coolers as a high-performance, low noise alternative to CPU coolers should be careful with their selections. It is not always possible to reduce the speed of the stock fans or replace them in order to reduce the noise generated by the kit. For example, the fan of the Cooler Master Seidon 120V is virtually noiseless when its voltage is dropped down to 7V; the pump however is not, making a clearly audible, high pitch noise. This is also true for the Enermax Liqmax 120S, as the pump of this kit makes a whining noise as well, although the noise of its pump is significantly lower. On the other hand, the Corsair H90 is not the best performing or, due to its size, the most convenient kit of the roundup, yet it is entirely silent when its fan's voltage is reduced down to 7 Volts.



Cooler Master

It would seem that Cooler Master simply wanted to create the best performing AIO coolers available. In that respect, they certainly managed to do so, as their Nepton series coolers are constantly at the top of our high load thermal performance charts. On the other hand, one would have to be at least partially deaf in order to use these coolers with the fans anywhere near their maximum speed. Even with their voltage reduced down to 7V, both kits are rather noisy. It is not possible to run these kits quiet even if you reduce the voltage even further, as the fans are clearly audible from 1 meter away even at just 4.7V, the minimum voltage required to start them. Therefore, we simply cannot recommend them to anyone seeking a quiet cooling solution.

The Seidon 120V however is an entirely different product. Priced at just $49.99, it is more of an alternative to an average air cooler than competition for liquid cooling solutions. It fares relatively well at lower loads but its performance diminishes with thermal loads greater than 150W. With an average thermal resistance slightly above 0.014 °C/W, it will most likely be unable to compete with most extreme performance air coolers, and it has a particularly noisy pump, making it noisier than other 120mm AIO coolers. However, it has other merits, as it does not stress the motherboard with its weight and it requires very little space around the CPU area, making it ideal for special builds and/or systems that are moved around a lot.

Corsair

Corsair has such a vast selection of AIO cooling products that we could make a roundup just for them. Each of the five coolers that they shipped us for this roundup displays entirely different behavior; thus, each of them is suitable for a different type of user.

With the H75 Corsair is offering a compact 120mm AIO cooler but with two 120mm fans for extra performance. The H75 performs relatively well, although it generally does better at thermal loads lower than 150W due to the low capacity of its small radiator. The use of two fans however increases the noise of the system, giving the advantage to Enermax's Liqmax 120S if low-noise operation is the top priority.

The 140mm H90 on the other hand displays great all-around performance and very low noise levels. Even with its fan constantly running at maximum speed, the H90 can be considered fairly discreet and is comfortable for everyday use. If quiet computing is what drives you, the H90 deserves a very strong consideration.

Corsair informed us that the H100i is their most popular AIO cooler and we can see why. Despite its size, the H100i easily competes with coolers using significantly larger radiators. The stock fans have a wide operating range and the USB interface allows the user to adjust the performance/noise ratio to meet his or her exact needs. Furthermore, the size of the radiator makes the H100i compatible with a relatively wide array of cases.

After looking at the performance figures of the H100i, we felt disappointed by the performance of the newly released H105. The H105 hardly performs much better and it only does so when the thermal load is very high. Unfortunately, the thicker radiator can create compatibility issues and it also is more expensive than the H100i, all while lacking the USB interface that the H100i has. It is hard to recommend the H105 over the H100i for the slightly better thermal performance alone, unless of course maximum thermal performance is virtually the only concern of the user and a larger radiator cannot fit into the system.

Finally, the last AIO cooler from Corsair that we have tested, the Hydro H110, possibly stands as the performance winner of this roundup. Although it does not have the best thermal performance, it is very close to the top of the charts and manages to do so while maintaining very low noise levels. However, the size of the radiator limits the compatibility of the cooler with only a handful of cases currently available and, considering that the retail price of the H110 is over $125 at the time of this review, it is a costly thermal solution.



Enermax

The two AIO coolers from Enermax that we had the chance to look at share a similarly sized, 120mm x 120mm radiator, yet they are absolutely nothing alike. The Liqmax 120S is a product designed with value in mind, to compete with AIO coolers in the league of the Cooler Master Seidon 120V and the Corsair H75. Its thermal performance is unimpressive, slightly worse than that of the Seidon 120V, yet the noise levels of the Liqmax 120S are considerably lower. It is unable to compete with the dual-fan H75 though, at least not while maintaining similar noise levels.

The Liqtech 120X on the other hand is very impressive, especially in terms of quality and aesthetics. A simple inspection reveals that the radiator and block of the Liqtech 120X are much better made than those of most other kits. It delivers good thermal performance while maintaining very low noise levels, considering the size of its radiator and the use of 120mm fans. The downside is that the Liqtech 120X owes much of its good performance on the extra-thick radiator, which could lead to compatibility problems with some cases if there is not enough clearance.

The only great problem that all AIO coolers from Enermax have is the low availability, as they currently are not available in North America at all and few retailers stock them in Europe. They can be imported to the US from Asia or Europe but that is a financially unrealistic option.

NZXT

NZXT currently offers only two high performance AIO coolers, both with 140mm wide radiators, which limits their compatibility significantly. On the other hand, they are the only coolers with extended (≈ 40cm) tubing, allowing the radiator to reach the front panel of a tower case. Still, the number of cases currently capable of supporting a 140mm wide radiator is quite limited.

Both the Kraken X40 and the Kraken X60 performed well in our tests, offering thermal performance similar to other AIO coolers of the same class. Specifically, they offer lower thermal performance than Cooler Master's 140mm wide coolers but maintain reasonable noise levels, while they display about the same thermal performance as Corsair's offerings but are not as quiet. While better fans could have been selected, NZXT has a tremendous advantage over the competition; the Kraken X40 and Kraken X60 retail for about the same price as other 140mm wide AIO coolers but only NZXT's offerings feature a USB interface. The USB interface allows the user to monitor and fine-tune the performance/noise ratio of the cooling system directly from the desktop, as well as to program custom LED lighting colors and effects.

Silverstone

Silverstone currently offers only two AIO liquid coolers, the Tundra TD02 and the Tundra TD03, both of which we have tested in this review. They are both based on the same design, with their only difference being the size of the radiator. Although the design of the Tundra TD03 is similar to that of the Enermax Liqtech 120X, the aesthetic design of Silverstone's offerings is quite different, going with a white/grey/nickel color theme instead of Enermax's black/red. The OEM behind them might be the same, although that is a mere guess on our part, as the fin design and frame of the radiators are significantly different.

The appearance, feel and quality of the Tundra TD02 and Tundra 03 are outstanding, greatly superior to that of most other kits. On the other hand, the overall performance of these kits actually disappointed us. It is by no means bad, as both of Silverstone's AIO coolers deliver thermal performance comparable to that of other similarly sized kits at reasonable noise levels and are especially efficient under low fan speeds. However, we expected a lot more from kits with radiators this thick and with such a classy appearance.

The mediocre performance may be due to the narrow corrugated tubing, a weak pump, a wrong choice of fans, or any combination of the above, but the fact is that a performance upgrade is required in order to overtake the competition. Furthermore, we are unsure about the white/grey color theme, as it will most likely stand out way too much inside all-black cases and that is not always the desired effect. Still, the balance between quality, performance, and value is very good and Silverstone's AIO coolers will become a favorite among those who want to combine low-noise operation and good looks. Just make sure that the 45mm thick radiators will fit inside your system before purchasing one!

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