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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  • ballsystemlord - Wednesday, January 24, 2024 - link

    Thanks for sharing.
  • charlesg - Monday, January 22, 2024 - link

    It seems like this would be bought by someone who likes Corsair, as anyone who does there research would quickly realize there are better options at this price point.
  • thestryker - Monday, January 22, 2024 - link

    Gone through a few reviews of this and it sounds like a top notch cooler when it comes to Intel. Once you go over to AMD though it is outclassed which makes me. wonder how well it will do with future Intel CPUs. If MTL is an example Intel is moving their CPU cores to the edge and will likely have the same problem as coolers with issues on AMD do now.

    All that being said Thermalright has come in and smashed the air cooling market. Unless you really like a specific look of a cooler they have products in the $30-50 range that keep up with or beat everything in the $100+ air cooler arena.
  • Threska - Monday, January 22, 2024 - link

    Long as the fans are easy to put on and take off, I'll be happy. A lot use plastic tabs.
  • erotomania - Tuesday, January 23, 2024 - link

    Thermalright use thin wiry paperclippy metal to clip fans on. It works but it's not the most satisfying.
  • m3city - Tuesday, January 23, 2024 - link

    That's a detailed review, thank you. I'd like to know how it compares to stock AMD Ryzen coolers. Is it worth to substitute the basic ones? I guess that stock coolers are designed to withstand each DESIGN state of CPU, including PBO in case of ryzen. Would such cooler allow e.g. higher clocks that lead to significant (in terms of measured, perceived) time gain in x265 encoding, rendering etc? I believe that such review without comparison to baseline product is somehow lacking.
  • TheinsanegamerN - Monday, January 29, 2024 - link

    What you are looking for is a deep dive on AMD architecture performance under different temperatures. A review of a single cooler isnt the right place to find this information.
  • zlandar - Tuesday, January 23, 2024 - link

    This looks like a copy of Noctua's D15 except it's currently $10 less.

    $10 is not enough of a discount. I would rather spend $10 more and buy a Noctua.
  • SanX - Tuesday, January 23, 2024 - link

    When you read about coolers that means that's time to take your computer outside, take garden blower and remove a megaton of dust on all its cooling surfaces
  • PeachNCream - Tuesday, January 23, 2024 - link

    Or just use a passively cooled computer so there's no worry about airflow. A fair number of laptops and mini PCs available for very reasonable prices fit such needs and work great for daily computing and light gaming fun too.

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