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 only manually. Fans can have significant variations in speed from their rated values, thus their actual speed during the thermal testing is being acquired 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 Noctua NH-U12A CPU Cooler Testing Results, Maximum Fan Speed (12 Volts)
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  • Skeptical123 - Friday, July 12, 2019 - link

    I think you're misunderstanding the target consumer here. Noctua has made such a solid product for so long now they have established themselves not only as a market leader but as a premium brand. Just look at the NH-U12A for example. While a very good product they raised the price higher giving it likely some of the highest profit margins of any cooler on the market because they can command that price. As their core market segment does not want water coolers no matter the price. Due to too many moving parts, etc. Or simply not have the room in the case and or not want ing to mess around with mounting a radator Reply
  • mobutu - Friday, July 12, 2019 - link

    Way way way too expensive so totally out of the realm of even considering this product.

    For Ryzen is even totally unnecessary unless your into heavy overclocking. You can get mild overclocking with the free included wraith cooler.

    Spending that 100 usdollars into a better cpu/gpu is a no brainer.
    Reply
  • sonny73n - Friday, July 12, 2019 - link

    +1

    Only idiots overclock the CPU and spend more money for the cooler.
    Reply
  • azrael- - Friday, July 12, 2019 - link

    There's some very important info missing from the review: the weight!

    The first thing I look at with a cooler is its weight, considering how most of them hang off the motherboard. There's a reason AMD and Intel have cooler weight recommendations.

    And yes, I know I can simply look up the cooler on Noctua's web site, but that doesn't change the fact that this information should be part of the review.
    Reply
  • jabber - Friday, July 12, 2019 - link

    People always go on about the Coolermaster 212 but it has the suckiest mounting system in HSF history. I detest the things. My heart sinks if a customer brings in a system with one of those. Reply
  • DanNeely - Friday, July 12, 2019 - link

    "Overall, the NH-U12A is designed to fit top-tier cooling performance into a more compact 120 mm cooler, as opposed to larger and more traditional 140 mm coolers."

    This seems like a bit of an odd turn of phrase. AFAIK dual 120mm fan tower coolers have been around almost as long as single 120mm models; which has been a lot longer than 140mm models of any sort started to show up.
    Reply
  • vailr - Friday, July 12, 2019 - link

    For half the price, the Scythe Mugen 5B (~$45 on Amazon) seems to offer equivalent CPU cooling. Reply
  • D@ Br@b($)! - Saturday, July 13, 2019 - link

    +1 and it's more quiet too. Reply
  • djayjp - Friday, July 12, 2019 - link

    Yeah sure 250W load at 7v and only like 55C lol. Bs Reply
  • Soulkeeper - Friday, July 12, 2019 - link

    What was the RPM on the fans ?
    Did they manage to spin at their rated 2000rpm during the testing ?
    Reply

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