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NZXT Kraken X61 & X41 Liquid CPU Coolers Review

AkG

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NZXT’s Kraken series of prebuilt CPU water coolers has been around since early 2013 and when they were released, they took the All in One market by storm. Since then, the original X60 and X40 are still among some of the better solutions around but the competition has been fierce with new or updated units from Corsair, Silverstone, Antec, Thermaltake and many others. Now NZXT is launching the Kraken’s next generation while consists of three new Asetek-supplied closed loop liquid coolers: the X31, X41 and X61.

In order to top of the performance abilities of their first attempts, NZXT went back to the drawing board. The result is a brand new waterblock and pump design that was handed down to Asetek for mass manufacturing. This update promises to be even more efficient at whisking away heat from even the hottest running of CPUs.

While absolute CPU cooling performance is first and foremost the primary task of NZXT’s redesign, the pump plays a key role as well. In previous AiO designs fan speeds could be controlled so a user could have some control over their system’s noise levels but the pump itself remained at a constant operating speed. This proved to be a bone of contention since achieving truly quiet acoustics proved to be a challenge with the pump chugging away. With the X41 and X61 NZXT is introducing a technology that’s long since been available on custom water cooling setups: a variable speed pump which can scale its speed from 2400RPM to 3600RPM depending on load conditions.

<div align="center"><img src="http://images.hardwarecanucks.com/image/akg/water_cooling/NZXT_Kraken_X61_and_X41/intro.jpg" border="0" alt="" /></div>
There are plenty of similarities between the newest Kraken series and their predecessors, NZXT has implemented more than enough changes to warrant a second look. A new fan dubbed the FX140 V2 was designed to improve overall airflow, radiators were updated with the latest technology and the NZXT CAM controller software has also undergone some noteworthy improvements.

Like their predecessors, the dual bay X61 and single bay X41 are based on the 140mm form factor and go for $140 and $110 respectively. While this may sound like a lot to spend on a CPU cooler, they’re supposed to offer some of the best performance around at minimal decibel levels. More importantly, both come with an immense 6 year warranty which does add quite a bit of long-term value to the equation.

On paper these two new coolers do have a lot going for them but with stiff competition from every corner, they’ll need to be extremely impressive to justify their relatively high cost.

<div align="center"><img src="http://images.hardwarecanucks.com/image/akg/water_cooling/NZXT_Kraken_X61_and_X41/x61/mfg.jpg" border="0" alt="" /></div>
 
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AkG

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X41 & X61; Points of Commonality

X41 & X61; Points of Commonality


Both the X41 and X61 may be from NZXT’s second generation of All in One liquid coolers but, other than their respective physical looks, there are quite a few differences between the two despite being designed by Asetek.


As with the oriental Kraken series, the list of accessories is classic Asetek in its scope and there are also a few pleasant surprises. Not only is there enough included equipment to mount the coolers to nearly any Intel or AMD system but the hardware itself has been upgraded to Asetek's latest design. This means the backplate with separate hollow threaded tubes is gone the way honest politicians, and has been replaced with a backplate that boasts integrated mounting brackets.

Also gone are the two-piece plastic spacers as they too have been upgraded to a much easier and simpler to manipulate integrated design. Interesting enough, this is not the first time we have seen this setup and the Kraken’s mounting hardware bears a startling resemblance to Corsair's H75. This does make perfect sense as both are based upon Asetek's latest and greatest design.

Interestingly enough, even though NZXT have included the necessary adapters to mount a second fan to the X41, that second fan isn’t actually included. On a single-bay AiO that costs over $100 this is a bit of a missed opportunity since the X41 includes a very thick radiator.


Another point of commonality between the X41 and X61 is the new FX140v2 fan. Like the coolers themselves, this fan has been thoroughly redesigned to provide higher amounts of airflow and operates at a lower noise envelope. However, it does have reduced static pressure specifications when compared against the previous generation and that may cause an issue given the aforementioned thick radiator on the X41. As we will see in a bit, the X61 doesn’t suffer from the same potential limitation since it includes a thinner radiator design.


The waterblock used on these units has also been upgraded in a couple noteworthy ways. It uses Asetek's latest design which was also implemented on Corsair’s H75 and incorporates a thoroughly redesigned mounting system. This is a key improvement since one of our major critiques of the X60 and X40 was their overly complicated installation process.

While the water block still utilizes a low profile, circular layout and integrates an LED that displays NZXT’s logo the real changes take place below its surface. In previous Asetek designs the water pump was usually rated for 2800-3000RPM and really was not meant to be run at anything less than 12V (the X40's official rating was 2900 -/+ 150 RPM). The new pump on the other hand has an operating range that starts at 2400RPM and goes all the way to 3600RPM.

This wide range means that it won’t be full speed during idle periods and can ramp up to higher levels only when needed, much like the attached fan(s) can. This flexibility in operating range means these coolers can be downright silent when required and only go into full performance mode when things stat heating up.

We can also see that NZXT added a trio of hard-wired meshed cables extending from the X41’s waterblock: a USB internal header, a 3 pin power cable and a double headed 4 pin fan controller wire which allows for up to two fans to be powered. Due to its higher power requirements when four fans are installed, the X61 utilizes the exact same connector layout but adds in two more fan connectors and a SATA power connector.


The base finishing is quite good but certainly not mirror-like in appearance. There aren’t any worries about this since it is perfectly flat and the thermal compound is formulated to fill in any imperfections.

Rounding out the waterblock's built in features is NZXT has once again opted for 90° connectors to mate the tubing to the water block. These swivel barbs do make the installation process even easier, but are fairly typical by modern standards. However, while par for the course, they are still a great feature which will reduce connector pressure and thus increase longevity.
 
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AkG

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A Closer Look at the Kraken X41 & X61

A Closer Look at the NZXT X41



On first blush the new X41 doesn’t appear to be all that different from the X40 it replaces. Both are Asetek built models and just like the X40 before it, the X41 uses a single bay 140mm radiator along with 14cm long 3/8” tubing and round waterblock. The real difference lies with the radiator which is a portly 36mm thick, making it the first 140mm AiO to use this design. It also points to why we are slightly concerned about the single fan; every 120x36mm All in One comes with two fans in order to efficiently move air through the densely packed fin array and optimize performance.


From first impressions alone it looks like the X41 should easily power past the X40 and usher in a new level of cooling potential for single bay AIOs. After all, a 140mm radiator has 36% more surface area than a 120mm design, so increasing the thickness to basically the same depth of that of a H80i (or any thick 120mm radiator AIO for that matter) should also boost performance.



Sadly, one area that could have used improvement, but was not noticeably upgraded is the X41's tubing. Just like the X40 before it the X41 uses 3/8th OD tubing instead of the much thicker tubing CoolIT uses in their designs. This is unfortunate as the new water pump should have the power to handle higher flow rates which could have further improved performance. On the positive side there’s a massive 16 inches of tubing included which should make for easy installation into very large cases.


A Closer Look at the NZXT X61



The Kraken X61 is a massive 280x140mm sealed water cooler that brings new meaning to the phrase “heavy duty cooling”. With that being said, from the tubes on down, it uses the same hardware and multi socket mounting system as its smaller X41 sibling.


Once you take a closer look at the X61 there is not much to distinguish it from the X60 it replaces at the top of NZXT’s lineup. While the X41 uses a massively thick radiator, the X61's radiator is only 27mm thick which means the only design improvements lie in the water block, fans and variable speed pump. This is unfortunate as a thicker radiator would have helped improve performance and also readily distinguish the X61 from the older X60.

On the positive side, a standard thickness radiator doesn’t usually have overly high static pressure requirements so quad fan configurations are most likely not needed in this case.


Instead of easily being able to tell an X60 and X61 apart via the radiator thickness, the X61 has to rely upon the other improvements NZXT and Asetek have baked into it. The largest of these improvements is the aforementioned waterblock / pump combination. In fact, NZXT has opted for basically the same pump as the X41.

As with the X60, the X61 uses 16” long 3/8” OD tubing, 90° barbs for the waterblock, and the same rats nest of cables shooting out of the waterblock. While they are once again sheathed in a tight mesh their length and quantity does make for a rather untidy appearance.

Taken as a whole these improvements may help the X61 distinguish it from the X60 but overall the improvements are not as significant as what NZXT did to create the X41.
 
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AkG

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Kraken CAM Software

Kraken CAM Software Overview



The first generation Kraken software was quite decent for a first generation application, but it was lacking both refinement and adaptability. The all new CAM software has obviously been designed to address these shortcomings as it is even easier to use while being much, much more intuitive. With that being said, it does take up a significant amount of system resources; about 8-10% of a 4770K's processing power.



After installing the CAM program the very first thing you need to do is create an online account with NZXT. This will only take mere moments but you will quickly grow frustrated with the password creation portion. At no point will it tell you all the various rules to password creation and instead will only tell you one of these unwritten rules you have broken. In our case we chose a simple password and it was obviously too short. So we made it longer. It then thought for a couple seconds and told us that it would not do as we had to include a number. After including a number, it then failed and told us to include a capital letter. Only then would it create our account. Ugh.



Once we did actually get into the program what we found it was worth the effort there are some rough spots that NZXT are trying to smooth over. As you can see the screen is broken up into a few main sections. The rightmost area is aptly labeled the 'specs' section and allows shows a simple overview of your system. If the Advanced Mode is pressed a new screen pops up with a much more detailed overview of the system.



On the right hand side is the Basic section which gives a real-time overview of system information. Below this is the Notifications section which can occasionally give some extremely odd readouts. For example it reported our GPU load had exceeded 98 percent, even though the system was idling the entire time. These minor issues are just that - minor and can be safely ignored as growing pains. Many have also been fixed in the latest versions.


To extreme right are the graphs and kraken app sections. These two areas are the real meat of this program and are where you can customize both the pump and fan speeds. In earlier revisions both the fan(s) and pump were a touch slow to update with their new speed after a manual configuration, but the latest version's interval between modification and application is much, much shorter. Overall this section is extremely easy to use and quite intuitive.

All these features are impressive but NZXT has also included cloud integration which allows you to control and fine-tune CAM aware devices via your smartphone or tablet. At this time this is limited to iOS devices, but an Android version is 'coming soon in November' but we’re well past that timeline. Unfortunately, on some phones the buttons are a bit too small and the adjustment for fan control extremely finicky. This complaint stems directly from the fact that we were forced to use an iPhone instead of our Nexus 7 tablet, but this is what most Kraken users will be up against as iPads are a tiny portion of the iOS user base. NZXT need to release the Android version and correct this lack of foresight ASAP as it does tarnish an otherwise excellent and innovative feature!
 
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AkG

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Setup and Installation (Intel/AMD)

Setup and Installation (Intel & AMD)




Much like the previous generation Krakens, the new X41 and X61 are OEM’d by Asetek and, like some of Corsair’s latest water coolers, actually use Asetek's latest generation mounting hardware.

Asetek has come a long way in the ease of installation department and both the X41 and X61 are fairly easy to get set up. With that being said they are not as easy as CoolIT-based units and their large 140mm form factors tend to decrease case compatibility. As long as your case can accept either a single or dual 140mm fan design these issues are certainly not deal-breakers by any stretch of the imagination.

Just as with their predecessor's the first step with these two new AIO's is preparing the back plate. Unlike the X40/X60, the new X41/X61 series use a much improved backplate design which we first saw with the Corsair's H75 and H110.

This backplate is and Intel-only affair instead of boasting dual AMD and Intel compatibility. Also, while this backplate is still made of plastic, each corner uses a slider with integrated standoffs for broader Intel socket compatibility instead of the older three-hole design that was highly prone to being stripped out. To use it simply slide each corner inwards for 115x systems and outwards for 1366/2011 socketed systems.


The next steps are self-evident and well detailed in NZXT’s installation booklet. The backplate needs to be moved into position and four standoff screws have to be installed. These screw down through the motherboard's CPU cooler mounting holes and into the hollow tubes in the backplate. This securely attaches the backplate to the motherboard and ensures the proper spacing for the waterblock.

Since NZXT has already applied the Intel retention ring so if you have a compatible system the last few installation steps are much simpler than they were on the X40/X60 series.


Since the X41 is a single 140mm radiator based unit the it only requires a case be equipped with a compatible rear exhaust port, though a top mount can be used in a pinch. Unfortunately, and unlike either the Kraken X40 before it or the newer Corsair H75, the X41 uses a thicker than usual radiator that has a rather deep base. Because of this it would simply not fit into our HAF-X case with the inlet/outlet ports facing downwards despite it boasting 140mm fan mounts. Only by changing the orientation and having them at the top (never a great idea) will it fit.



The X61's larger radiator will make proper case selection key to the success or failure of your installation. Before purchasing it, take a close look at your case’s top exhaust ports and make sure they have 140mm mounting holes which feature the necessary offsets. This does make it a trickier install, but considering how large this device is, it's not any more difficult than most modern AIO models from the various other manufacturers. That extra long tubing helps immensely.



AMD System Installation




Since both the X41 and X61 rely upon the same Asetek hardware, installing them onto AMD AM2, AM3, FM1 and FM2 systems follows the same basic footsteps as the Intel process. The only difference between the two is the hardware components being used and a lot more work as both are preconfigured for Intel systems.


The first step is to remove the stock AMD top bracket, but keep the stock backplate in place to thread four standoff screws onto the motherboard.


With all four standoff screws installed and the backplate once again securely attached to the motherboard the next step is to prep the waterblock. This means first removing the stock Intel mounting hardware by gently prying off the four plastic retention clips from the metal top bracket. These retention clips are integrated into the bottom plastic ring so care will have to be taken to not break any of them since they need to reapplied afterwards. With the bottom black retaining ring removed the Intel top bracket can be changed out.



As with the Intel installation, mounting this setup to an AMD motherboard hinges upon the proper alignment of Asetek’s “tooth” setup. The issue here is just getting everything into place since there’s a chance that during the change-out between the two brackets, something will break.


At this point both the X41 and X61's installation follows exactly the same path as their Intel installation. Mount the waterblock, secure with the four thumb screws, install the radiator and plug in the fans. Overall, this complicated procedure makes the AMD installation seem rather antiquated and outdated compared to what CoolIT units have to offer, but it is still a fairly straightforward process.
 
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AkG

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Test System & Testing Methodology

Testing Methodology


To ensure that the results from one review to another are not only reproducible but actually pertinent to this review, the Testing Methodology will be the same throughout all water cooling review. If something does change we will be sure to make a special note of it and explain why this change was done and more importantly why things had to be changed or altered.


Thermal Paste and Application Methods:

Arctic Cooling MX-2 thermal paste was used for all water based CPU cooling solutions during these tests unless otherwise noted. Application of thermal paste was in accordance with the TIM manufacturer’s instructions; and while not necessary, the TIM was allowed to cure for 24 hours under moderate to high loads (with periods of low loads) prior to testing.


Fans Used:

120mm:

For all water based CPU Cooling Solutions which do not come standard with a fan, a pair of Noctua NF-P12-1300s and a Scythe S-Flex “G” 1900RPM fan will be used if it accepts 120mm fans. With these two fans we are able to simulate different fan speed conditions as indicated below.


High Speed:

1900RPM Scythe S-Flex “G”. To be more precise our specific fan runs at 1860RPMs. Any stock fan which comes with the ability of being controlled by means other than the motherboard (e.g. remote fan speed controller, potentiometer, rheostat, etc) will be set to this speed during the High speed test and BOTH sets of performance results will be included.


Dual Fans:

Dual NF-P12-1300s

*Dual fans only used if the cooler comes with the necessary mounting hardware.


92mm Fan:

If the cooler being tested only accepts 92mm fans, a Noctua NF-B9-1600 will be used.

If the given CPU cooling solution comes with a stock fan we will also include its numbers in the closest of the main tests BUT we will also include our standard fan results in that particular tests.


Fan Notes:

- If a water cooling solution cannot mount an aftermarket fan, we will be only including the stock fan results. However, if the stock fan speed can be precisely controlled by means other than the motherboard BIOS (an included remote fan speed controller, potentiometer, rheostat, etc), the cooler will be tested at different fan speeds.

- For dual fan results ALL water coolers capable of mounting two fans (and come with the necessary hardware) will be tested with two NF-P12s and the Dual Fan graph will contain data for other such dual capable fan coolers.

We feel that the combination of multiple speeds and multiple fans will allow us to give you our readers clear and precise idea of the capabilities of a given unit, in an accurate comparison. It will also help eliminate the occasional “zinger” such as when a manufacturer includes an extremely high-speed fan in order to possibly offset poor thermal performance.


Environment:

Except where noted all comparison testing was done inside a closed case with a room ambient temperature of 24c. If at any time the room temperature increased or decreased by more than 1°C, testing was halted until the temperature constant was re-established.


Testbed:

The case chosen for this test bed is a Cooler Master HAF-X. We chose the HAF-X as it a highly adaptable case with not only multiple fan ports but is capable of handling even the largest of AIO coolers. To populate these fan ports we chose Scythe E 120mm units with Sony Fluid Dynamic Bearings. Unless otherwise noted, only one of the top two exhaust fan ports, the rear exhaust port and front fan intake port will be populated. The front fan port will use the stock CM 230mm fan. The rear exhaust port will be populated by the review item's fan and radiator where possible, for the air based cooling alternative used in the review as a counter example another Scythe E will be used.


Warm Up:

Before testing commenced 15 minutes of running Prime95 “small fft” followed by 45 minutes of idling was done. This warm up period was done at stock CPU core frequencies. This additional pretest was done to ensure that the fluid in the liquid CPU cooling solutions were at ambient room temperature and thus the test results would be more indicative of real world scenarios. For all air based cooling solutions the same 15 minutes of heavy load followed by 45 minutes of idle was also done.


Temperature Recording:

Recorded temps were as reported via the Real Temp plug-in for the RivaTuner monitor program.

Max and Average load temps are based on 15 minutes of running Prime95 “small fft” and are taken directly from RivaTuner’s built in capabilities.

The maximum temperatures will be the highest recorded temp displayed for any of the cores during the 15 minute test. While RivaTuner will display each core's average temperature it does not easily show the average of ALL the cores. To this end we will be simply taking the average of all the cores adding them together and then dividing by the number of cores.

If during any test temperatures of 95°C or more are displayed in RivaTuner (for any core) for more than 10 consecutive seconds the testing will be halted and that test run will be considered a "fail".

Idle temperatures are the lowest recorded temperature during idle period as recorded by the RealTemp Rivatuner monitoring program.

All CPU throttling technology was disabled in the BIOS; as was all CPU fan speed control. In addition, Turbo Mode was disabled and Hyperthreading was enabled. All power connectors for the review item are connected directly to Molex connectors to ensure they were running at full speed.

All tests are run a minimum of three times and only the best results are represented.


Charts & Graphs:

Each chart will include the Maximum or “peak” temperature we recorded, the average temperature and the idle temperature.

No passive results will be shown UNLESS manufacturer claims the ability to passively cool a processor. If a manufacturer claims passive capabilities we will include the performance numbers in the charts. The only exception to this is if the review is a “review roundup” and to keep the charts from becoming confusing we may not do so.

All water cooling reviews will also include a air based CPU cooling which best approximates the price range of the water cooling solution being reviewed. This way you will not only know how it compares to other water cooling units but also an Air based CPU cooling solution which is in the same approximate price range.


Sound Pressure Testing:

To give a more accurate and less of a personal opinion on the noise level of the stock fan which accompanies the heatsink, we have included a new section for sound pressure testing. These tests are done in our open case setup outlined above with the meter positioned 30 inches away from the cooler and mounted on a tripod. To ensure the background noise does not skew the results all tests will start by recording the ambient noise of the room. Only when it meets our standards will the testing commence.

To ensure that no external noise unduly skews the results, the GPU used will be a passively cooled unit and the only active fan will be the one on the cooler while the PSU and HDD are isolated away from the immediate area.

These tests are run late at night when no other people or animals are awake and thus unable to influence the results.

All fans are run at their maximum speed with no voltage or PWM control being used during the sound pressure tests.

The sound pressure meter used is a DT-805 which has been professionally calibrated and NIST certified. We will record the highest levels obtained with said meter and record it as our result. The test will be 15 minutes long and will be run while the fan is running full speed via a Molex connector and the CPU cores are under a full load via Prime 95 Small FFT.


Please note: The Scythe S-Flex G and Noctua NF-P12-1300 (at 1300 and 900rpms) numbers are taken when mounted to a Cooler Master Hyper 212+. We feel that it would be extremely unfair and unrealistic to include noise rating for these after market fans if they were NOT mounted onto a cooler. They are included to help give some sense of proportion to the charts and allow you to more easily compare a stock fan against a known quantity.


Complete Test System:

Case: Cooler Master HAF-X
Processor: Intel i7 920(Intel)
Motherboard: Gigabyte X58-UD3R
Memory: 6GB Mushkin Silverline Stiletto DDR3-1600
Graphics card: EVGA GeForce GT 240
Hard Drive: 1x 240GB Intel 520 SSD
Power Supply: Topower Powerbird 900W

Special thanks to Gigabyte for their support and supplying the i7 motherboard.
Special thanks to NZXT for their support and supplying the NZXT 140mm fans.
 
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AkG

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Stock & Fan Performance Results

Stock Fan Performance Results


<div align="center">
<img src="http://images.hardwarecanucks.com/image/akg/water_cooling/NZXT_Kraken_X61_and_X41/26.jpg" border="0" alt="" />
<img src="http://images.hardwarecanucks.com/image/akg/water_cooling/NZXT_Kraken_X61_and_X41/34.jpg" border="0" alt="" />
<img src="http://images.hardwarecanucks.com/image/akg/water_cooling/NZXT_Kraken_X61_and_X41/38.jpg" border="0" alt="" />
</div>

Without moving away from the Kraken series’ default fan speed profiles a few things are apparent. First and foremost the X61 is simply a cooling <i>beast</i>, but one that is only slightly better than its predecessor. Of course this was to be expected as the X60 was a phenomenal CPU cooling solution from day one and getting massively better results would have been next to impossible given the relatively minor number of changes built into the X61. The fact of the matter is the only way to noticeably improve performance over that of the X60 is either move to even higher performance fans (or more of them) <i>or</i> go to with an even thicker radiator. NZXT did neither, so while the improved waterblock can slightly boost performance some of it is lost from slightly slower fans.

Turning our attention to the X41 we can see that the thicker radiator is actually a bit of a detriment to overall stock cooling performance. Time and time again thicker radiators have required <i>two</i> fans for optimal performance and that doesn’t seem to change here regardless of the improvements build into the included fan. NZXT really need to consider another one of their fans with the X41 so it can deliver optimal performance. More about that on the next page.
 
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AkG

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Dual & Quad Fan Performance Results

Dual & Quad Fan Performance Results


<div align="center">
<img src="http://images.hardwarecanucks.com/image/akg/water_cooling/NZXT_Kraken_X61_and_X41/dual.jpg" border="0" alt="" />

<img src="http://images.hardwarecanucks.com/image/akg/water_cooling/NZXT_Kraken_X61_and_X41/quad.jpg" border="0" alt="" />
</div>

Adding another fan the the X41 allows it to compete with many current generation 240mm and even some 280mm AiO coolers on the market. This just goes to show that had NZXT added that other fan right off the bat, they would have had what is arguably the best single-bay closed loop liquid cooler on the market.

Moving on the the thinner Kraken X61, the resulting drop in temperature with four fans installed is impressive but nowhere near what the X41 achieved in terms of raw cooling performance increases.
 
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AkG

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Fan Comparison / Sound Testing

Fan Comparison


NZXT claims their new FX140 v2 fans are an improvement over the previous generation models and on paper at least, they are. With the ability to move more air than their predecessors, the comparison should be straightforward but in augmenting certain abilities, their static pressure envelope has actually decreased. By offering up static pressure like a sacrificial lamb, NZXT may have improved airflow and acoustics (more on this later) but actually optimizing a radiator’s performance requires more than just pushing air inefficiently through a dense fin array.

In order to compare new and old fans in an apples to apples environment, we set them up on some of NZXT's AiO coolers and ran our standard tests.

<div align="center"><img src="http://images.hardwarecanucks.com/image/akg/water_cooling/NZXT_Kraken_X61_and_X41/dual_2.jpg" border="0" alt="" /></div>

The results above are very interesting since it looks like the older FX140 is able to outperform the new fan by a very slim margin despite operating at the exact same speed, regardless of which cooler was being used. The difference won’t be noticeable and certainly won’t aid in improving an overclock but this just goes to show the value of static pressure.



Sound Level Testing


While everyone "hears" noise differently there is one easy way to remove all subjectivness and easily compare different fans: use a sound level meter. All fans are tested with both voltage regulation / PWM turned off so they represent a worst case scenario, detailing how a cooling setup would sound when it is under full load.


While within our charts the FX140 v2 on the X41 and X61 seem provide an slight improvement over the acoustical profiles of their predecessors, there are a few caveats. First and foremost among these is the actual sound these fans make. While the first version exhibited a muted hum, when the coolers are under heavy load, the FX140 v2 makes a high pitched noise which is very hard to ignore.

With that being said, that annoying noise is only evident when the fans are operating at 11V or higher. At 10V they lose the squeal and become rather easy to live with. This is actually better than the original FX140 which needed to go even slower before their buzz disappeared.

Overall, the FX140 v2's are bit of wash from a noise perspective, but high performance fans are always loud and if you want them to be quiet you need to keep them from hitting full speeds. Due to the CAM software's ability to quickly tame the v2 fans, we can actually give them a passing grade here.
 
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AkG

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Conclusion

Conclusion X41


With the Kraken X41, NZXT took a tried, tested and true product and thoroughly updated it to better compete within a highly competitive segment. Many of the updates paid dividends in a big way, making this one of the best single bay All in One water coolers on the market.

The improvements here are subtle but they make a big difference when compared against the X41’s predecessor, the venerable X40. The installation process has been simplified so novices won’t have problems adapting the AiO to their system, NZXT’s CAM software is now highly intuitive and very capable, the new FX140 V2 fan nets some acoustical benefits and the extra thick radiator provides some performance advantages. One of the crowning additions is variable speed pump which remains blissfully quiet in idle scenarios and ramps up well when the system is under load.

There are some areas that still need to be addressed though. While the new fan design does provide higher amounts of airflow, it just cannot overcome the thick radiator’s static pressure requirements. As a result cooling potential is artificially capped. Adding a second fan really brings performance up to a level that competes with the last generation’s dual bay 240mm solutions but sadly NZXT decided to include just one. That thickness can also bring about some installation challenges even on cases that support the 140mm form factor.

While the Kraken X41 has some imperfections, NZXT has shown what can be accomplished when a thick single bay radiator is paired up with a 140mm form factor and an innovative pump design. At $110 this certainly isn’t an inexpensive cooling solution, particularly since it only includes a single fan but there’s enough here to have hope for future iterations.



Conclusion X61


Many of our comments regarding the X41 also apply to NZXT’s Kraken X61 but there are some fundamental differences which help make this cooler stand out. It may not offer all that much more raw performance than its predecessor but it does provide a significantly better value.

With the X61, NZXT stuck to a well defined formula and chose to keep radiator thickness to a standard 27mm. Not only does this ensure broad compatibility (or as broad as a 280mm form factor will allow) but the FX140 V2 fans’ cooling potential is able to shine through. This doesn’t allow for a huge performance advantage over the immediate competition but there’s enough differentiation here to place the X61 at the head of the proverbial pack.

Even without the X41’s 38mm radiator design the X61 incorporates plenty of its smaller sibling’s defining features. Its pump is silent when it needs to be, the CAM software provides more than enough customization and installation is a relative breeze due to the extra long tubing and a straightforward mounting process. A number of these additions allow the X61's dual fan results to narrowly beat the X60 equipped with a quartet of fans. Now that's impressive.

Like any savant the X61's specialty is narrowly focused, but like most it fails at being great at everything outside this focus and requires more fans to truly shine. It may be great at cooling, but it ultimately fails to provide a compelling argument as to why consumers should choose it over any of the other (sometimes cheaper) dual 140mm radiator based AiOs already on the market. By that same token if you are not loyal to any brand and want one of the best closed loop liquid coolers that money can buy, the X61 should be on your short list.


 
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