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

The NZXT CAM Software Testing Results
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  • QB - Thursday, August 20, 2020 - link

    I ran my H80i for close to 8 years (not sure the exact date, but it was at least 7 for sure) and only retired it this year for an iCUE H110i RGB PRO XT. Not a single leak, and it only suffered from a minor amount of liquid permeation... If I was to guess how much liquid disappeared over the 7+ years based only on the sound of the liquid moving around the radiator, I would say it was maybe 25%. I did not "need" to retire it, but with all new gear sitting under it, I figured an all new cooler was also warranted :)

    QB
  • silencer12 - Thursday, August 20, 2020 - link

    Repeat after me. You will eventually be using liquid cooling since air cooling will not be able to keep up in the future because processors will generate much more heat.
  • Guspaz - Thursday, August 20, 2020 - link

    Air cooling can handle a fully loaded 280W threadripper without trouble. Consumer chips are still at 105W. I think we’re good for a while yet. Liquid cooling does not substantially outperform air cooling until you go larger than 240mm rads, where space can become a concern.
  • Luminar - Thursday, August 20, 2020 - link

    Future processors will generate much more heat?

    Are you talking about Intel's processors in 2022 (if Intel still even exists)?
  • Unashamed_unoriginal_username_x86 - Thursday, August 20, 2020 - link

    Intel isn't going to up and disappear because they lost the DIY segment, it has 10x the revenue of AMD, and a lot of market share for AMD to bite into still.
    Speaking of the DIY market, it's very popular to overclock there, and the biggest bottleneck outside of if it's unlocked is thermal management.
  • silencer12 - Thursday, August 20, 2020 - link

    Yes, future processors will generate more heat. Likely, in my opinion. I am talking more than 2-4 years in the future.

    Intel made 71.9 billion (2019). Of course they will exist. They are coming out with their own graphics cards.

    @unshamed explained the rest already for me below on market share.
  • PeachNCream - Friday, August 21, 2020 - link

    I don't think you will see widespread need for water cooling in desktop PC hardware in the near future. Not when the average desktop CPU currently sits between 35-65W TDP with a few halo models reaching to +95W. Compute resources have to meet other targets besides more instructions per second in order to be economically viable products. That, of course, dismisses enterprise workloads in data centers where I think liquid cooling might be a more reasonable consideration and where packing as much density into a given rack while having the staffing and vendor support to handle potential liquid cooling is a fair bit more doable.
  • silencer12 - Friday, August 21, 2020 - link

    Acknowledged.
  • Tom Sunday - Thursday, October 8, 2020 - link

    I just purchased my all new prebuild PC from my local 'strip-center' tech-shop for $800 cash including a used RTX 1080 ($95) from a cryptocurrency miner since the mining days are now virtually a thing of the past. Yes...Intel has a lot of cash and more even today after just spinning off one off their subsidiaries. NVIDIA just paid $40 billion for ARM. Making CPU's? Corsair went public and looking at their "S1-document filing" made Mr. Paul (CEO) a cool $100 million with stock options. My Reality: The boys at the computers show were laughing that some highly touted AIO's now costing more then brand new older generation CPU's.They said that AIO water-cooler purchases applies to less than 20% of all customers or people coming to the show. Furthermore that the total USA motherboard market represents up to 90% of solely 'mainstream boards' between $90-$125 and which generally do not overclock. Madnu said..."For the man on the street cash is tight." I am not good with numbers and marketing and many other things so what do I know? But listening to the 'geek-team' from Bangladesh I inherently know something is not right with the hardware prices as touted on the open market. Paying $280 for a AIO? Meanwhile I am back in my basement command center listening to the Mugen-5 humming along. Playing Fallout 4 for the very first time in 'Max' settings. Today Mom is baking a strawberry pie. Life is good.
  • Beaver M. - Friday, August 21, 2020 - link

    Judged by what?
    AMD, whos CPUs always were running hotter/less efficient than Intel at the same manufacturing process?
    Intel, who is still stuck with hot-headed 14 nm CPUs?
    Dont make me laugh. Telling the future by the unique situations we have now, is pretty nonsensical.
    Even in 10 year, its more likely that manufacturers will optimize their case ventilation and/or space for air coolers.
    I mean, most midi cases have space for 4 to 6 more D15-size air coolers, that isnt used at all.
    Its long due time for a new standard anyway. ATX is 25 years old!

    And before I put some crappy AIO in my case, I rather build a water cooler myself for a few hundred bucks more.

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