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, Packaging & Bundle Testing Results
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  • BattleRam - Friday, January 15, 2021 - link

    Is this compatible with TRx40 AMD cpu's? Reply
  • evilspoons - Friday, January 15, 2021 - link

    On the first page:

    "It is large enough for most commercial processors but will not cover a ThreadRipper processor, for which the Freezer II coolers have no stock support for out of the box."
    Reply
  • WarWolverine - Friday, January 15, 2021 - link

    I was looking for 360mm because it was $120 for amazon a week or 2 ago but now they are sold out. But yesterday 420mm was available off amazon for $160 so I grabbed that. Hopefully it'll fit into my Phanteks Pro. Replacing Deepcool Captain 360 from 2017. Kinda an overkill for a 5600x. With Deepcool I'm getting 73C and lots of throttling 5600x @ 4.85Ghz (kryonaut thermal paste). Reply
  • Holliday75 - Friday, January 15, 2021 - link

    Yeah the 360's are hard to find. I got lucky and picked one off of Amazon at MSRP a few weeks back. Reply
  • schujj07 - Friday, January 15, 2021 - link

    In reality all of the Liquid Freezer IIs are hard to find. When you do find them, typically they are selling for over MSRP. Reply
  • nils_ - Saturday, January 16, 2021 - link

    I couldn't find the 420 version in Germany, the 360 was available however. Might just upgrade later. Reply
  • Makaveli - Saturday, January 16, 2021 - link

    lol kinda overkill a 420mm on a 6 core 5600x 65watt tdp chip indeed. Reply
  • WarWolverine - Sunday, January 17, 2021 - link

    Update: the 420 cooler came in. It took me over an hour to put in. It almost didn't fit. CPU power was in the way, I had to force it a few millimeters out of the way. I ran 3D mark time spy like I did with 360 Captain and I got 70C vs 73C. Mobo fan curve is set to Performance. It does improve cooling and it takes longer to heat up but it does heat up. I did a stress test with cpu z for a few minutes and it did heat up to 72C. I am OCing 5600x to 4850 with PBO 2. Undervolt curve on 4 cores at - 15 and 2 best cores at - 5. I'm kind of disappointed that the best cooler I can get only delays the heat and not keep the the CPU under 70C. Maybe if I manually OC it will have lower temps. Maybe I didn't put enough kryonut thermal paste. I'll try to re-do it later. I will try to replace the fans with NH U12A 3000rpm fans later. Reply
  • TheWereCat - Sunday, January 17, 2021 - link

    I was able to get the 360mm for €90. I replaced the NH-U12A which was the same price. Now I get about 20°C less at also lower noise... 3900X CPU. Reply
  • Showtime - Friday, January 15, 2021 - link

    Surprising that it has become a thickness race already. You still get to claim top performance at x dimensions with a caveat (that it won't fit lol). Thinner fans could help, but that will cost more, and be louder. Reply

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