The Kraken X40 breaks the current trend of closed-loop water coolers rocking 12cm fans by upping its fan size to 14cm fan, which NZXT promises delivers more heat dissipation and better cooling without subjecting users to deafening fan noise. It’s a lofty promise, but having tested it, we can tell you that this Kraken's bite lives up to its bark.
The X40 offers unrivaled cooling performance on quiet mode.
The X40 is based on Asetek's fourth-generation all-in-one closed-loop design, which features a copper cold plate that has been improved with denser micro-fins and a new center channel to increase coolant flow. A single NZXT FX-140 PWM fan is included, and the cooler supports an optional second fan for a push-pull config. It's compatible with all modern CPU sockets, with the exception of LGA775, but faces a larger compatibility obstacle in that it requires a case with a 14cm fan, such as NZXT's own Phantom 410. The X40 also sports extra-long 16-inch rubber tubing compared to most other closed-loop systems that use tubes measuring around 12 inches. Accompanying the larger fan is a wider radiator that offers 36 percent more surface area than smaller 12cm rads.
Like Corsair's H80i that we reviewed last month, the X40 has an LED on top of the pump that you customize to either remain a solid color or to change color depending on temperature, which is slick. We also appreciate that the software to control it comes bundled on disc, whereas Corsair's software requires a download. The software is easy to use and allows you to adjust fan speeds, but not pump speeds like Corsair's equivalent. While it features only two presets, “silent” (1,000rpm) and "extreme" (1,700rpm), as opposed to the half-dozen with Corsair's software, you can still manually set the fans to run at fixed RPMs and save custom profiles.Installing the X40 was relatively easy. With our LGA2011 backplate preinstalled, we began by inserting four screws through the retention ring that allows the water block to be mounted to the CPU socket. The X40 features a similar retention ring to Thermaltake's Water2.0 Pro, which snaps onto the water block with a retention clip. This mounting process isn't as straightforward as the H80i’s simple magnetic mounting bracket, but the X40’s manual features excellent illustrations that simplify the installation process. Mounting the radiator and fan to the chassis just required tightening four screws through the back of the case. The last step was to connect the CPU fan and USB cables to the mobo headers, and unlike the H80i, all the cables come pre-attached to the water block, and the pump doesn't require additional power (Molex or SATA), making the installation less of a hassle.
In testing, the Kraken X40 was impressive, and we were pleasantly surprised to find that the preset silent mode not only lived up to its name, but cooled extremely well, hitting just 67 C under load. This was enough to whoop our Hyper 212 zero-point air cooler in performance mode by 7 C, and it also bested the 12cm Seidon 120M water cooler running on full blast by 1 C. With the X40’s fan cranked to maximum, it gave Corsair’s H80i a run for its money even though we had it running in push-pull mode with two fans, which was quite impressive. While the X40’s fan can be mistaken for a small leaf blower at full speed, it fortunately doesn't need to operate at its highest speed to cool well.
While the X40 isn't cheap at 100 bones, it’s no costlier than its peers and it outperforms them, making this cooler easy to recommend. If you have a case that supports a 14cm fan, you should definitely release the Kraken!
Super cool and quiet; customizable and easy-to-use software.
Clash of the Titans (2010)
Expensive; requires 14cm-compatible chassis.
NZXT Kraken X40 (Quiet mode)
NZXT Kraken X40 (Performance mode)
CM Hyper 212 EVO (Performance mode)
Cooler Master Seidon 120M (Performance mode)
Corsair H80i (Performance mode)
Burn - Ambient
All temperatures in degrees Celsius. Best scores bolded. All tests performed using an Intel Core i7-3960 at 4.2GHz, on an Asus P9X79 Deluxe motherboard in a Thermaltake Level 10 GT with stock fans set to High.