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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  • Oxford Guy - Monday, April 4, 2022 - link

    PC enthusiasts are living in a strange fantasyland where CPUs need so much space and money devoted to efficient cooling but GPUs do not.
  • theunshackled - Tuesday, April 5, 2022 - link

    With power requirements rising on the next generation of RTX GPUs, either we look for our own adequate thermal solutions or let the manufacturers handle it themselves. The thing is though...I highly doubt that the 3rd party GPU vendors will sell cards without pre-built cooling, unlike the best 12th gen/Zen unlocked CPUs.

    That extra premium we pay ASUS/GIGABYTE/MSI/etc. to cool the GPUs are often good enough. I I agree that the reference fans/thermals, however, are often paltry.
  • meacupla - Tuesday, April 5, 2022 - link

    That is such a dumb statement that totally ignores the fact that GPUs don't have a standardized mounting design where you can attach a standardized water block built that will fit.

    No, instead, we get a standard mounting hole around the GPU, but completely different plate designs that cool RAM and VRM for almost every single card out there, making cross compatibility a nightmare. This is why we get these asinine $400 GPU blocks that only fit one card, and why most AIO watercooler manufacturers stay the hell away from a GPU AIO cooler.
  • Oxford Guy - Tuesday, April 5, 2022 - link

    ‘That is such a dumb statement’

    If you’re referring to my post you’re way off because hacking on a water cooling system is hardly relevant to most enthusiasts. Water cooling loops are complex, expensive, and a hack.

    I was obviously speaking to standards, standard equipment. If GPU makers had switched to the Fury X design of integrated water that would be a different matter. They have not. Only a few cards ship like that and they’re ridiculously overpriced. The existence of even the 3090 Ti in air-cooled form should be enough evidence for anyone to prove my argument.

    The market is bizarrely warped into heavy space and cooling-to-noise ratio for CPUs and giving GPUs using vastly more power short shrift.
  • Oxford Guy - Tuesday, April 5, 2022 - link

    And, by referencing Fury X I was not implying that only a 120mm radiator integrated with a GPU is necessarily adequate. Here, once again, we have a triple-fan radiator for a CPU. Where are the triple-fan water-cooled radiators integrated into GPUs?
  • Nomgle - Wednesday, April 6, 2022 - link

    They're on the market - https://www.sapphiretech.com/en/consumer/toxic-rad... as an example.
  • Oxford Guy - Monday, April 11, 2022 - link

    No doubt at an extremely premium price + an overclock that helps to negate the benefit.

    There is a big difference between that an something considered much closer to standard equipment.
  • Moonub - Saturday, April 23, 2022 - link

    I’m with you Oxford Guy. We need GPUs to start offering a standard option for extra cooling - basically give us a mount of a GPU AIO cooler, right ? It would be great. I guess for the card manufacturers, they are selling the cooler as part of their value add and don’t benefit from opening up the GPU as a platform for other cooling products. This is probably what holds this back.
  • shabby - Tuesday, April 5, 2022 - link

    Pepperidge farm remembers when intel used to include coolers with their cpus... but only to hit the base clock 😂
  • Khanan - Tuesday, April 5, 2022 - link

    You can mod your GPU, never saw waterblocks? And that’s just an example.

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