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 Cooler Testing Results
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  • tygrus - Thursday, September 7, 2023 - link

    You can use a closer distance (eg. 12½cm) & assume at 1m will be much quieter. If ideal then at 12½cm is 18dB louder than at 1m, in reality it maybe 12dB different. At >1m a speaker sounds would drop 6dB per doubling of distance. 2x 24dB of the same sound would be 3dB louder than 1.
    2x perceived volume adds 10dB.
  • deporter - Friday, September 8, 2023 - link

    >You can use a closer distance (eg. 12½cm) & assume at 1m will be much quieter.

    Yes, sure, but they measured from 1 meter. It says so on page 2.
  • mr2ns - Friday, September 8, 2023 - link

    In the first paragraph of the Conclusion "Wrapping things up..."

    1) I am not sure if the performance description "within the realm of mediocrity" and the assessment "without significantly sacrificing effective heat dissipation" go together. You must have a low initial expectation bar for mediocre to not be a significant sacrifice.

    2) While I certainly agree with professionals you included “enthusiasts”? We appear to have different ideas of what constitutes an enthusiast. Is an enthusiast just someone that owns a pc and runs it stock? I feel like we have another low expectation bar here. I am a big believer that everyone has their own use case but unless they are silent pc enthusiasts, I have trouble accepting that “enthusiasts” who significantly prioritize noise to the point of accepting mediocre thermal performance are anything but a niche market.
  • PeachNCream - Saturday, September 9, 2023 - link


    1) It really is mediocre among AIO water cooling in terms of results so that's 100% reasonable.

    2) No one, to my knowledge, has gotten that specific about what constitutes an enthusiast aside from the fact that, in terms of people that own PCs, they are a pack of idiots that are easy to sell googaws to by slapping a fast car, dragon, or a big boob girl on the package in order to pump them for money while they aspire to waste electricity and manufacturing capacity.
  • mr2ns - Saturday, September 9, 2023 - link

    right, I wasn't disputing the mediocre, just saying that calling it mediocre than saying that using it isn't sacrificing effective heat dissipation are not congruent thoughts.
  • meacupla - Saturday, September 9, 2023 - link

    It can handle a 340W load. It's more than enough for desktop CPUs.
  • mr2ns - Saturday, September 9, 2023 - link

    Where did "handle" even entered this conversation? Literally every cooler in the chart can handle 340W but without you providing some further context to what you mean, what does that have to do with the price of fish?
  • meacupla - Saturday, September 9, 2023 - link

    Do you know how to read graphs? It's pretty obvious you can read, but can you comprehend what is being said?

    Look at the graphs for Maximum fan speed, Core temp, 340W.
    It says "25.8C delta over ambient".
    That means, if you're in a 20C room, core temp would be at 45.8C.
    That would be a good result.
    If you can't understand that, you need to go back to school.
  • mr2ns - Monday, September 11, 2023 - link

    Yes, I know how to read but that really isn't the question so much as can YOU read, or did you just jump into a random comment to ramble off course?
    I pointed out that the author called thermal performance mediocre THEN goes on to say, "without significantly sacrificing effective heat dissipation". Those thoughts are not congruent. They do not agree. Pick one, not both.
    Do you understand what I am saying now, or do you REALLY want to continue shaking your fists at the sky about what it can handle? The performance was never my dispute, the author’s contrary thought expression is. So again I ask you, how does your initial or elaborated comment disagree with my expression that the author’s two thoughts do not belong together? It seems to me that you agree with me as you contend it is a good result, not mediocre as the author stated.

    If you were intending to respond to PeachNCream where they said that its performance IS mediocre then there is a handy reply button, and probably always was, after their comment instead.

  • PeachNCream - Tuesday, September 12, 2023 - link

    Please don't drag me into this one. I get what you're saying but I was trying to add a little more context. Modern writers often stop writing, look at a phone, and then resume. That creates disjointed thoughts like the one you highlighted as a bit mismatched. I get it. I even agree to an extent, but I also see the fact that it doesn't really stand out all that much among water-cooled AIOs so it still makes a bit of sense even if its obvious the writer was distracted and no one bothered to do any editing before publication.

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