NZXT Kraken X40 140mm AIO CPU Cooler Review

NZXT finally delivers its 140mm AIOs to our lab for testing. It's time now to check out the Kraken X40.

Manufacturer: NZXT
17 minutes & 24 seconds read time


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While it does say right on the Kraken box that NZXT was first in the world to deliver a 140mm AIO cooling solution, we were not sent this cooler upon release. While everyone else was taking a look at what these new larger AIO coolers had to offer users, I was given the pair of Respire coolers that almost seemed like some sort of a bad joke. In the mean time I reviewed the pair of worse than average, budget air cooling solutions; the rest of the world was looking at why we are here today. In the meantime, while NZXT was trying to find me samples, Corsair snuck in and delivered a pair of 140mm cooling solutions to have a look at, so at bare minimum, at least we have a similar setup to compare the Kraken to.

We will be starting with the smaller of the two offerings from NZXT. They have released a more standard solution with a single 140mm radiator, based on an Asetek cooler design. What came to mind as soon as I got my hands on these units were the older Antec 620 and 920 coolers. Why I say this is based on two things. One is the light up head unit, but it is more than what Corsair offers with their standalone units. The Kraken series works with a USB cable connected and offers software control of all sorts of things, and unlike with Corsair, you do not have to buy the Link to obtain this level of control. The software is the second reason, as it not only gives you fan speed control, pump speed control, and lighting control, but you also have readouts for all of these things, plus you can keep an eye on the internal liquids temperature to see just how efficient these coolers are, or how close to saturation you really are with a wild overclock.

Today, we are going to start off the series with the Kraken X40 from NZXT. This is a single 140mm radiator AIO that uses high FPI count in the radiator, and match the system with a decent fan to cool the tight nit area. With an increase of 36 percent of surface area, the 140mm solutions seem very good for this application, and as we saw with the H90 and H110, these larger units do offer better cooling than most 120mm solutions, even some of the dual radiator setups. With the bar already set from Corsair, we can now have a look at NZXT's offerings and see if the first in the world means best in the world.

On paper things seem to be leaning to the NZXT solutions, but we have hit the point to where we will see for ourselves what NZXT has brought to the table, and see if there are any reasons to choose these over the Corsair solutions.

Specifications, Availability and Pricing

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Starting with the head unit, if you flip it belly up, you can see the convex copper base plate that takes the initial heat load from the processor, and through skived grooves in the back of the plate, the pump included in the head unit forces coolant through these grooves to remove the heat from the CPU. On the head unit of the X40, of course you have two black rubber tubes connected to the side, attached to swivel fittings to make installation cleaner and easier, but it also offers an assortment of cabling near these connections. On the end of the three braided leads that emanates from the head unit, there is a 3-pin fan connection to supply power to the pump which runs at 2900 RPM. The other two leads terminate in a USB connection so the software has a way to talk to these units, and the other lead ends with a pair of male 4-pin fan connectors to allow users to clean up the wiring to install the stock fan, or a pair of them for a push/pull setup.

After passing over 15 inches of rubber tubing, the longest in the industry, you then run into the aluminum barbs that the tubes have been connected to on the radiator. This radiator is of course made of aluminum, measures 27mm thick, and uses a fin count of 24 FPI. With this much surface area, and such a tight fin arrangement, it is going to take a really good performing fan to make this unit efficient. Here NZXT chose the FX-140RX-PWM fan. This fan offers 98.3 CFM at 2000 RPM. While it is powered with a 4-pin connection for PWM control, the static pressure rating of 2.2mmH20 should be sufficient enough to push through this radiator. On top of offering a two year warranty on these units, you can also see that they will mount up almost all of the CPUs in use today, providing the chassis they are in offers a 140mm fan hole in it.

Since these cooling solutions have been on the market for over a month now, finding the X40 online was not very tough at all. Currently the best deal that I see is at with a listing of $92.93, shipping included. While there are a couple more listings before I ran into the price, OutletPC and Newegg I have at least used over the years, and can say you will get what you pay for with them. While the price does increase about $2 if you shop at, I am sure more people will go there just for the familiarity and security in the purchase.

Coming in at just under $100 is a good start to trying to dominate the AIO cooling segment, but there is more than just simple specifications and a lower price to keep in mind. Let's get into the finer details of the Kraken X40 from NZXT and see how much cooler you get at this price.


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The packaging is mostly white with the splash of blue colors to impress the look of water behind the image of the X40 shown up close on this panel. You can see they claim the first 140mm solution, and the fact that this comes with a two year warranty.

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Spinning things around to the right, you now see a listing of the supported CPU sockets at the top. This is followed with an explanation of the increased surface area these offer over 120mm solutions. It then finishes off the information with a comparative thermal chart of the X40 versus a thick and thin 120mm solution.

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On the back you get a couple more images of the X40 along with a story behind why NZXT went this way, and what it should offer the customers. On the right side there is a list of four features that should make you lean to this solution over 120mm solutions, and possibly over other 140mm solutions as well.

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The last side of the packaging takes the entire panel to display the specifications. I will say this, on specifications alone, most customers will be more informed of what is inside this box than many other AIO solutions, as they tend to keep the specifications more limited in other offerings.

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Inside of the box you will find the same recycled cardboard tray that all Asetek units ship in. With paperwork shipped on the top, the unit sets inside of compartments to keep the fans and head unit from reaching the radiator. Just in case something does get loose, there is a cardboard sleeve on the radiator so that none of the fins will be damaged.

NZXT Kraken X40 AIO CPU Cooler

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The round head unit is a dead giveaway of this being an Asetek kit, but unlike most, this head unit from NZXT will illuminate. Both the ring and the NZXT name are fully RGB programmable via the software to match any system, or denote the coolant temperature with a scale from green to red.

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The black rubber hoses use a sleeve to keep them attached to the plastic swivel fittings of the head unit. You can also see that right next to the tubing are three braided leads coming out of the head unit.

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These leads are to power the head unit with the 3-pin fan connector at the bottom, the USB plug is to allow software to talk to the X40, and the top lead ends with a pair of 4-pin can connections to keep the wiring at the radiator clean, and enables the software to set the fans speeds.

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For transportation and sanitary reasons, the head unit is shipped with a clear plastic cover. This will keep anything off the copper surface, and it will help keep dirt out of the thermal paste.

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Speaking of the thermal paste, it is pre-applied in a large circle in the middle. This will cover an entire IHS, but since I test all coolers with the same TIM, this textured application needs to be removed.

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With the paste out of the way you can definitely see the circular milling marks left behind on the copper plate. There was no dirt in the TIM, and the surface of this base is in really good shape for testing.

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I have been mentioning that these new bases are pretty convex, so I grabbed a razor to show you. As you can see the base is very high in the middle, but with the pressure of the hardware kit, it does help this round shape conform to the flatter IHS you are putting it on.

NZXT Kraken X40 Continued

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What I do like about these kits is the use of 15 inches of tubing to give users the extra bit of room that the other kits don't offer. The three pin fan connection is eight inches long, the pair of 4-pin fan connections are nine inches long, and the USB cable is 22 inches long to easily get to the USB ports on your motherboard.

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As the tubing reaches the radiator, again there is a pressed sleeve used to keep the tubing on, but this time they are attached to aluminium barb on the radiator.

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This radiator is 138.4mm wide and stands 172.5mm tall. That means this radiator may be a little large for the rear panel even if there are 140mm fan holes there, but won't cause much issue if installed at the top or anywhere else in the chassis for that matter.

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From top mounting holes to bottom mounting holes, this radiator stands 27mm tall in this image. While that is for the entire frame, the radiator is only 20mm thick.

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Choosing a random spot in the radiator to measure, with the tight fins behind the tape measure, you can count the individual fins. This is where I got the figure of 24 FPI count for this review.

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Grabbing the fan from the box, you can see once it is installed, it almost doubles the thickness of this system. With one fan you are dealing with 52mm of thickness now, and if you want to do a push/pull setup, you need to consider that the radiator sandwich will then be 77mm thick.

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I just wanted to get the head unit and the radiator in the same image, so here it is. Take it all in for a moment and get ready to take a look at all the hardware you need to mount to this cooler.

Accessories and Documentation

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It doesn't matter whose name is on the kit, the hardware is all the same as the other Asetek units. Here you have the AMD top and bottom plates on the left, the lock ring in the middle, and the Intel bottom and top mounting hardware on the right.

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You also get four bags full of goodies. At the top left are the LGA2011 legs with the universal set in the bag below it. On the right there is the top bracket hardware, isolation foam pads, and the metal inserts for the back plates. The last bag at the bottom offers eight long and five short fans screws and eight washers to give you everything you need for any installation.

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We saw the paperwork when we first opened the box. What I didn't see at first was that they also stashed a CD with the software on it, into the folded paperwork. So once the X40 is installed, you can either insert this disc, or venture to the NZXT website for the software.

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One side of the paper offers the Intel mounting in eight steps. It also offers a full listing of the components included so you can verify ahead of time that you have what you need to get the X40 into your rig.

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The AMD mounting instruction don't offer the contents section, but it does take the same eight steps to install the X40. Basically everything is the same except for steps one through three where you add in the pads and pick the correct top and bottom mounting kit.

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The last bit in the kit is the FX-140RX-PWM fan included with the X40. While the specifications are really good, I also like the contrast of the nine white blades against the fans frame, and more importantly, as it is attached to the radiator in your chassis.

Installation and Finished Product

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If you are using AMD, there is only one hole in that back plate to install the metal threads into. With the Intel kit, look closely, as it does say which hole is for what socket, and for our testing, I set them in the 1155/1156 holes.

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After that I flipped over the plate and installed the foam isolation pads. While the back plate is plastic and likely won't short anything, there are a few solder points that these do buffer against on my board, and every little bit of protection helps.

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On the head unit, once you have the top ring in place and set the tabs into all the notches around it, you then have to clip in the lock ring to keep this hardware secure and in place for the rest of the installation. I would like to note that this ring seems a bit larger than normal and was a real pain to get it locked in.

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In each of the four holes in the metal top ring, you need to install the top plastic clip into the lower section, and again they are marked. Here I have the 1155/1156 marking facing out so that it fits my board. Once those are clipped in, you just push the screw through them and you are ready to go.

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Since the holes for the 1155 mounting are offset, it does leave the back plate on an angle in respect to the motherboard, but it matters little to its ability to work or add the correct pressure around the socket.

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Than all you have to do is flip the board over, and attach the head unit via the four screws. Don't worry about the pressure here, just screw these in until the threads stop, and let the engineering of the X40 work for you.

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Stepping back a bit, you can see there is plenty of tubing to allow this radiator to make it to the back of any chassis with 140mm fan support, and easily reaches the top. With this much tubing, you can actually reach the bottom in some mid-tower cases, and it makes optical bay installation mods much easier.

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Once powered on, you can have control of the LED lighting system. While the X40 does offer 16.8 million color choices with the RGB scale, I simply chose one to highlight the feature as I cannot take images of every color combination.


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Whether you go to the NZXT website as I did to get the software, or you install it off the included disc, this is what you get when it first opens. This is what is called the dashboard. Here you get a reading of the coolant temperature and the fans speed at the top. The two windows below offer you the CPU temperatures which for some reason didn't show up when I took this image, but later worked as tests were performed. The last window covers the speed of the pump.

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The software also offers a graphing feature for logging temperatures and fan speeds. The top chart will show the speed of the fans, and this is in extreme mode and with fans that should spin at 2000 RPM, they are only reading at 1700 in this chart. As for the temperatures it is currently taking a measurement once every 30 seconds, as that is minutes of the hour and seconds being displayed.

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In the fan settings, you can change the fan speed. In the Extreme mode it is currently running, you can see the wild curve should have allowed the fans to run at their full speed, as the 68 degrees we got in the tests is past the 100% setting at 61 with this mode. You get a much more normal curve for silent mode; it just takes much longer to reach full speed. Then with the custom mode, you can slide any of those five blue balls on the chart to levels that you see fit for your demands.

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Light settings are where you can address the color of the head unit. At the top you can either slide the three sliders or use RGB codes directly input into the boxes to the right of them, and shows the current color you are trying to achieve in real time. There are also effects, where you can allow color change by temperature, what color to fade to, and it will pulse the lighting when the color changes. You can also set the temperature where this happens, the interval of the strobe, and how long the light stays on.

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In the general settings, there is everything else you could need. You can swap the temperature scale, start this app minimized, auto-start, and enable the statistical logs and at what durations. Along with being able to select your language for the software, you can set notifications for the liquid temperature if it goes over a certain temperature, and you can even add a tolerance of a few degrees to that setting. You also will be warned if the fan speed goes to low, sort of a failure warning so that if the fan does die, you don't take out the rest of the cooler and possible the processor if speed step is disabled with your overclock.

Test System and Thermal Results

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I would first like to thank HIS, GIGABYTE , InWin and AVADirect for supplying products for me to test with.

Testing for the CPU coolers is done with the use of RealTemp to ascertain temperatures, Intel Burn Test to deliver the load to the CPU and CPU-Z to verify the CPU speed and the voltage being used in Windows. All of the testing is done with an ambient temperature of 24.5-25�C and humidity is maintained to 35% sometimes less.

For the "stock" runs, it's more of a plug and play setup where the PWM of the motherboard is in control of the fans speeds for both the idle and load results. Speed Step is active and the processor idles at 1600 MHz and loads at 3500 MHz for the stock settings. I also set the memory to run at 1600 MHz for stock. As for the overclocked runs, I load the CPU at 4.5 GHz and idle results are obtained with 7.5V to the fans while the load run is set to deliver 12V to the fans. This allows me to gauge the lowest and highest fan ratings for my charts.

You will also see that the charts have been slightly adjusted. From now on I will mention the idle temperatures if there is something worth noting other than an average of twenty-five to twenty-seven degrees as the PWM controls and SpeedStep allow for almost ambient results in most instances. What you are now getting is a stock speed loaded temperature chart and an overclocked loaded temperature chart. To clean up the audio results, I also removed all of the fans that aren't on the thermal charts. If you want to compare those results to new coolers, the old chart is still available in the older reviews.

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When loading the 2600K at stock levels, the X40 does quite well. With a 47 degree result here, the X40 jumps into fourth place overall. For this test the pump was at 3000 RPM, the fan reached 1150 RPM, and the highest coolant temperature I saw during the runs was 33 degrees.

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Once the overclock was applied and the tests run, the X40 does drop a few places, and you can see where the dual radiator units pull slightly ahead of this. A top ten result is very good for any cooler, and 68 degrees is very respectable. For this test I used the extreme setting of the software which pushed the pump to 3200 RPM at times, allowed the fans to spin at only 1700 RPM - I could not make them reach the 2000 RPM advertised speed. As for the coolant temperature, at this point I saw results just below 38 degrees.

Noise Level Results

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Audio testing was a bit of a letdown. While I could obviously hear this cooler across the room, even at stock levels, the 32 decibels of noise level leaves the NZXT Kraken X40 slightly below average and louder than the Corsair versions of this cooler.

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When you set the software to the Extreme mode and allow the fans to power up fully, the noise is not shy at this point. Dropping way down to near the bottom of the list, a 58 decibel level here is on the verge of annoying, even when inside of the chassis. To be honest, I was gaming with a headset through part of this testing and could easily hear the X40 at these settings right over the game track and chat going on.

Final Thoughts

NZXT really did their homework here. I have seen quite a few of the AIO solutions that have hit the market, and not since Antec jumped into the market was there a solution as full featured as this unit is out of the box. Not only do you get the obviously larger cooler with the Kraken series of coolers, where you do get 36% more area to cool the coolant inside of the loop. Even with three wires coming out of the head unit, the fact that they are sleeved with braided nylon really keeps the wiring super clean when installed in a chassis. One other thing I really liked that I remember was a slight issue with the Antec version, the USB cable on the NZXT Kraken is more than long enough to use on any current motherboard and have no issues reaching the USB ports. Speaking of additional length, for those that don't want to install this in the back of the chassis, the 15 inches of tubing between the head unit and the radiator open the possibilities of locations inside of huge cases to mount this. The last thing that really bumps this product up another peg is that without an extra purchase, you can fully control every aspect any user could ask for via the software.

The performance of the NZXT Kraken X40 is really good, sliding right in with the Corsair H110, which is a solution that offers a dual 140mm radiator, so that is really saying something for the Kraken series. There is a downfall to this performance increase though, and that is the fans. While it only takes one look at the audio results, specifically the overclocked run where the fans were allowed to assume their maximum potential, they were loud. To be able to hear this fan through the headset while gaming is one thing, but without them on, there was a steady drone of a hum coming from across the room that drowns out three other PCs in the same room. On the flip side, you aren't always going to want to run the Extreme profile, but if you are benching or gaming with a heavy overclock, I would get those fans pumping at this speed sooner than later, or expect the thermal results to climb. I do like that there is software to make finite settings to the system, because with just motherboard control, you get wither PWM control if the board offers that, or you can max everything out. With the handy and easy to use software, it almost trumps the loudness of the X40.

Considering that the H90 is the head to head competition for the Kraken X40, NZXT is priced exactly the same on Newegg. So not only do you get slightly more performance at the expense of sound levels, you also get the software to gain complete control of the X40, but the fully customizable choice of colors on the head unit, it may be what AIO buyers are looking for, but missing from most other offerings out there. All things considered, I am willing to overlook a bit of noise to gain this amount of a performance increase, and since we are talking apples to apples with the H90 and the X40, there is no conceivable reason to buy the H90 with this being offered. Why on earth would you give up on the LED lighting and software, just for the name over the CPU?

In reality, this is the cooler to beat right now, and since NZXT was first in the world with a 140mm solution, I wish I had these before the Corsair units, as I may have been a little harsher with those designs than I was at that time. Seeing what NZXT brought with the Kraken X40 AIO, there really is not a better single 140mm radiator cooled solution being offered right now.

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Chad joined the TweakTown team in 2009 and has since reviewed 100s of new techy items. After a year of gaming, Chad caught the OC bug. With overclocking comes the need for better cooling, and Chad has had many air and water setups. With a few years of abusing computer parts, he decided to take his chances and try to get a review job. As an avid overclocker, Chad is always looking for the next leg up in RAM and coolers.

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