The NZXT Kraken Z63 & X73 AIO Cooler Review: Shiny On Top, Solid Underneath
by E. Fylladitakis on August 19, 2020 11:00 AM ESTTesting 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, steady and variable, as the thermal resistance also varies depending on the magnitude of the thermal load. Therefore, even if it would be 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 much 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 and or compatibility. The thermal cartridge inside the core of our testing station can have its power adjusted between 60 W and 340 W, in 2 W 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 the 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, their measurement is being performed manually. Fans can have significant variations in speed from their rated values, thus their actual speed during the thermal testing is being recorded via a laser tachometer. The fans (and pumps, when applicable) are being powered via an adjustable, fanless desktop DC power supply and noise measurements are being taken 1 meter 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.
The noise floor of our recording equipment is 30.2-30.4 dB(A), which represents a medium-sized room without any active noise sources. All of our acoustic testing takes place during night hours, minimizing the possibility of external disruptions.
| <35dB(A) | Virtually inaudible |
| 35-38dB(A) | Very quiet (whisper-slight humming) |
| 38-40dB(A) | Quiet (relatively comfortable - humming) |
| 40-44dB(A) | Normal (humming noise, above comfortable for a large % of users) |
| 44-47dB(A)* | Loud* (strong aerodynamic noise) |
| 47-50dB(A) | Very loud (strong whining noise) |
| 50-54dB(A) | Extremely loud (painfully distracting for the vast majority of users) |
| >54dB(A) | Intolerable for home/office use, special applications only. |
*noise levels above this are not suggested for daily use
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silencer12 - Friday, August 21, 2020 - link
When I read that AMD re-hired Jim Keller 2015-2016, I was glad and ecstatic. I knew that would bring AMD back. I support the underdog and want them to stay in business. I may be currently on an intel processor, since AMD was $400 for there zen processors generation 1 when it launched. Now, there are whooping Intel, and gaining their marketshare back. GOOD!That was not nonsensical.
Off- topic. This is even more unique situation. If was not nonsensical to know the pandemic (covid virus) would over-run the united states with President trump's response to it back in January / February. Had he acted early-on like he should have. Their may be less deaths and faster time in finding a cure that works. 177,000 people have died and rising.
Quote (President Trump) - I have very important people working on this. I can't say who they are, but it is very important people.
Beaver M. - Saturday, August 22, 2020 - link
Yeah, I too have a 6 cylinder engine.Get your script fixed, bot.
silencer12 - Saturday, August 22, 2020 - link
Do you even know what a bot is?I am certain you do not.
Beaver M. - Monday, August 24, 2020 - link
Someone who talks to someone about a topic that is completely off-topic.Hence my car comment.
If you think I dont know what a bot is, then I am very confident that you dont even know what conversational logic and reason is.
If it quacks like a duck...
thestryker - Wednesday, August 19, 2020 - link
It would be really nice if you could include some OEM information within the article in the case of closed loop coolers. I'm aware that this is an Asetek cooler because of prior information, but it's easily possible to not know.I would like to second the prior comment about adding a noise normalized test. While thermal performance is predominantly what I care about knowing the overall quality of the out of the box experience is really important to anyone who isn't going to replace the fans.
Tilmitt - Wednesday, August 19, 2020 - link
Would be nice if you could include an ARCTIC Liquid Freezer in your testing, it's pretty highly regarded.MDD1963 - Thursday, August 20, 2020 - link
Finally, the numbers people want *most* when they go to AIO/water coolers....thermal resistance, and, most important at all, how well it handles cooling a full earth-shattering 60 watts of heat!!!!Unashamed_unoriginal_username_x86 - Thursday, August 20, 2020 - link
The graphs go up to 340w, you have to select it...PeachNCream - Thursday, August 20, 2020 - link
Aside from being yet another rebrand of the same old AIO design, I don't think the complexity of NZXT's pack-in software is going to ultimately be of much benefit while at the same time having the potential of causing both security issues via increased surface of attack (and potentially poor or no response to discovered exploits) and system stability problems by tapping into and interacting with hardware. That has been and continues to be a problem with a lot of smaller companies with ambitious plans to add value to mechanically similar products through software. All of that extra code doesn't do much but add cruft in the same way we used to deal with TSRs back in the DOS era that were shoddy or wasteful of system resources.Quantumz0d - Thursday, August 20, 2020 - link
GN's tests always show AIOs are less loud and have better performance. But with the idea of having a machine reliable with no requirement for any sort of water damage. I would chose Noctua high end Air Cooler only. Yea it looks bulky and all, but I prefer peace of mind rather than these cooler products where they show off those RGB RAM sticks and what not, where that CAM bloatware and unwanted bloat is needed for the machine too.