NZXT Kraken X61 AIO Liquid CPU Cooler Review

NZXT is known to many enthusiasts for its computer cases but not so much for its Kraken series of CPU closed loop liquid coolers. After a year of design NZXT has introduced its new Kraken X61. Its claim to fame is that it is the "world's first variable speed liquid cooler." Let's see what this variable RPM pump does for the new Kraken.


It’s been a while since we’ve heard anything from NZXT’s cooling division. About a year, to be exact. The last coolers we looked at were the X60 and X40 which gave us good performance but were priced a bit oddly; AKA, uncompetitive.

So when the new NZXT Kraken X61 AIO Variable Speed Liquid Cooler arrived at our doorstep we were ecstatic to begin testing it and see what, if any, improvements NZXT made and where it will land in our charts. NZXT has redesigned the fans for radiator cooling which NZXT states will allow for increased performance at lower sound levels. The Kraken X61 also comes with extended tubing making it easier to fit into larger towers. Lastly, NZXT has given the Kraken X61 custom software controls which isn’t all that different until you realize it has mobile integration allowing you to monitor and adjust the fans remotely from your mobile phone. This is already an impressive list of updates, but the one thing we appreciate is something that has not changed at all; that is NZXT’s Kraken 6 year warranty. If six years doesn’t sound like a lot than consider that six years ago the pinnacle of CPU cooling was an air cooler made entirely of copper on a 3GHz CPU. Fun times.

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System Setup

Today's review takes place on our fourth generation [H]ard platform. The test bed consists of the ASUS Z87-Deluxe motherboard, eight gigabytes of Corsair 1600 MHz DDR3 RAM and the Intel Core i7 4770K.

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Test Methods


The biggest change you will notice is the removal of hardware testing. In recent years, Intel has shifted their methods of testing to software based and so we find it acceptable to do the same.


Once again we have an integrated GPU in our processor which alleviates the need for a discrete one. With the removal of a discrete GPU comes the advantage of not having an additional variable to account for.

The iGPU will not create any anomalies in our testing as long as we practice consistent testing methods.


Corsair was kind enough to provide us with their Carbide series chassis. It provides excellent airflow and interior space and is a good reflection on current case design.

Thermal Paste

Noctua's NT-H1 thermal paste was selected as the paste of choice for a few key reasons. The thermal paste has been shown to provide excellent thermal conductivity allowing the heat sinks to better do their job. There is no observed curing time. That is, performance does not get any better over time. Any curing time could have introduced variables into the equation causing at best dubious results and at worst unreliable ones.


Ambient temperature will be kept at 25C for the duration of the tests and measured with a MicroTemp EXP non-contact infrared thermometer and cross referenced with the Sperry Digital 4 Point thermometer. Any variance greater then 0.2C will halt the testing until temperatures return within spec for fifteen minutes.


Idle temperatures will be recorded after a twenty minute period of inactivity. Any fluctuation during the last sixty seconds will reset the timer for an additional five minutes.


Load temperatures will be recorded after a twenty minute period for air cooled systems, and thirty minutes for liquid cooled systems, at 100% load. To obtain this load we will be using AIDA64 Extreme Edition v3.00.2500. This places an even greater load on the CPU than before and includes some benefits. Because the load is so extreme we see the temperature vary wildly from 72C to 86C in some instances. To get an accurate reading we will utilize AIDA64’s ability to average the temperature over time. Given twenty/thirty minutes at 100% load we arrive at a temperature that accurately represents our heatsink’s performance.


Sound levels will be measured with a Reliability Direct AR824 sound meter from a distance of four feet away. With everything turned off and the room completely silent the meter registered a sound level of 38dB(A). This is a very quiet room where a simple pin drop could be heard. All sound measurements are recorded in the very late evening to further reduce any ambient noise.