Testing 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

Introduction & The Kits Testing Results
Comments Locked


View All Comments

  • meacupla - Friday, June 9, 2023 - link

    The radiators are low impedance, and fans are high air flow designs, but would that combination not work better if there were not wide open gaps between the fans?
    Like maybe cover the gaps up with paper board or something?
  • Oxford Guy - Tuesday, June 13, 2023 - link

    'The nine-blade design suggests that these fans are geared more towards airflow than maximum static pressure, substantiating AlphaCool’s claims that their NexXxoS radiators have low airflow resistance.'

    No, it doesn't. It can very easily mean that the fans are the wrong type for the radiator. That isn't a new thing to happen with these.
  • zmeul - Friday, June 9, 2023 - link

    I'd replace the fans with Arctic P12 MAX
  • sparkuss - Friday, June 9, 2023 - link

    Would be nice to have just a custom AIO from some of these parts with a choice of their GFX fullcover blocks. I have a case that I can hang it right next to the Roof AIO (Thermaltake Level 20 XT) currently on my CPU
  • garblah - Friday, June 9, 2023 - link

    I'll probably never spend as much money on a CPU for a gaming build as the lower end model of these two liquid coolers cost. 5800x3d for 280 USD and a 60 dollar air cooler is where it's at.

    But I still like reading about how much I could be spending, and wondering what I would get out of that.
  • Makaveli - Friday, June 9, 2023 - link

    I like their AIO for GPU's with current gen makes sense 360 Rad on something that put out 350+ watts. I have a 5800X3D also much cheaper Corsair 150 AIO on that barely needs that. If I was using a 13900K then would jump on something like this.
  • PeachNCream - Sunday, June 11, 2023 - link

    True! The least expensive of those two cooler kits is still priced at $365 which literally only gets you a cooling solution. You get no actual functional hardware and for the same price, you can get a fully working laptop with lower-end specs that can actually do useful things and have a bit left for software, accessories, and whatnot.
  • Samus - Saturday, June 10, 2023 - link

    That is a radical fin design compared to the typical heater core flat-folds used in most liquid cooling kits. Stamping and folding a sheet of fins like that without inconsistency is impressive.

    But everything has a trade off and this one is going to be maintenance. Keeping those fins clean and flowing sounds like a nightmare as the hooks latch onto every bit of dust passing by.
  • Oxford Guy - Tuesday, June 13, 2023 - link

    'Copper, of course, is one of the best thermal conductors out there, but the downside is that copper is both heavy and very expensive'

    Does the oxidized layer also insulate significantly?
  • shadowx360 - Saturday, June 17, 2023 - link

    Genuinely curious about the size of their target market chasing such an extreme end of the performance scale. I’d rather get an Arctic Liquid Freezer II and pocket the electricity savings of not pushing that kind of TDP.

Log in

Don't have an account? Sign up now