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 Corsair A115 Testing Results
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  • meacupla - Monday, January 22, 2024 - link

    I'm confused as to what the main selling point of the A115 is. It doesn't offer any tangible benefit over a D15.
    No, not even those maglev fans are an enticing selling point.
  • erotomania - Monday, January 22, 2024 - link

    "however, we hoped to see MagLev fans included. "

    What MagLev fans? :)
  • meacupla - Monday, January 22, 2024 - link

    I admit I misread that part.
    IMO, FDB is better than maglev.
  • ballsystemlord - Tuesday, January 23, 2024 - link

    Out of curiosity, why? What evidence did you use to form that opinion?
  • meacupla - Tuesday, January 23, 2024 - link

    it's purely anecdotal.
    At the top it doesn't get any better than Noctua's SSO bearings with Styrox fan.
    Just below Noctua, there is Nidec/NMB FDB used in various designs.
    Corsair's maglev sits in the marketing hype wagon. Better than DBB, SBB, or sleeve, but not as quiet as FDB.

    Maglev bearing is a good idea in principle, but it's not beating 20+ years of refinement that FDB has gone through.
  • Maksdampf - Tuesday, January 23, 2024 - link

    As far as i know Maglev is a Marketing Name by SUNON, one of the biggest Fan manufacturers in the world and has beend around since at least 20 years (1999 in fact). I have had Sunon Maglev Fans on my Pentium3 already.
    Corsair is just copying old and proven taiwanese tech here for which the Patents probably expired just recently. But they are not only copying the tech but also the Brand line "Maglev", which i find quite impudent. If Sunon hat their brand names protected well enough in the US, they would have a really good case here against the worlds biggest Brand of riddiculously overpriced Fans.
  • meacupla - Tuesday, January 23, 2024 - link

    I know of Sunon. I hated their fans because they were always loud at the bearing level.
    If Corsair copied their maglev bearing design, they sure haven't improved upon it.

    If you are that familiar. Back in the P3 days, the fan to get was Panaflo Low/Med model with their hydrodynamic bearings. Although NMB and Delta existed back then, they were not a good choice for desktops at the time.
    If you would also remember, HDB was such a game changer, that it spawned a bunch of copies that didn't infringe on Panasonic's patent for it. This includes SSO and FDB.
  • HideOut - Wednesday, January 24, 2024 - link

    And if Sunon didnt get sued by train companies that started maglev what, 40 years ago?
  • MamiyaOtaru - Tuesday, January 23, 2024 - link

    got 6 Corsair maglev fans in my computer. In a couple years two of them have started grinding, becoming unbearably loud. Replaced one, will do so with the second soon. By contrast, the 6 FDB fans in my computer from 2007 are all still going and sound fine, though there's one that I have to start spinning manually now (won't start itself) after which it spins fine. All in all a lot better result.

    Might just replace all the maglev fans with FDB instead of waiting for the next one to croak
  • MamiyaOtaru - Tuesday, January 23, 2024 - link

    my old FDB fans are Scythe S-Flex fwiw. Not made anymore afaik but I'm sure there's something equivalent, from them or someone else

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