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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  • AstroGuardian - Monday, July 15, 2019 - link

    Don't even think about using a boxed Ryzn cooler. That BS is crap. Reply
  • Qasar - Tuesday, July 16, 2019 - link

    at least a cooler is supplied with a ryzen cpu, and seems its pretty good for a " stock " cooler. intels cpus dont even come with one Reply
  • AshlayW - Tuesday, July 16, 2019 - link

    They are not "crap". The Wraith Prism is a fantastic cooler considering its size, and even has RGB. It has quad cooper heatpipes and can handle the 2700X at 4.1 Ghz all core (let alone the 3700X with its lower power use). It is sufficient for running stock 3900X or a very slight all core OC on the 8 core parts. And as someone else said, it's certainly a lot better than the "competition".... which doesn't even include one.

    The Wraith Spire and Stealth are adequate for their respective CPUs, at stock. You don't have to pay a single penny extra to get your system up and running, with the "K" series from Intel,add $30 onto their asking price just to get a cooler.

    Sorry for the long comment, just wanted to combat the misinformation
    Reply
  • AshlayW - Tuesday, July 16, 2019 - link

    copper* , sorry fat fingers Reply
  • Dragonstongue - Tuesday, July 16, 2019 - link

    ahem careful there
    "among the best fans" absolutely, best is VERY far stretching IMO
    also, just because they list for $30 per fan ($20 is about highest average usually ~$15 + ship etc)
    that is NOT their cost, take at base price say $15 per =$30 the cooler alone another $30 = $60 they should list at not $100+, why is quite simple actually, when you are producing something that is at best middle ground for 150w coolers it should not be priced above the vast majority of even top end coolers, not when there are so very many options to choose from, even from a "niche"
    Reply
  • GreenReaper - Thursday, July 11, 2019 - link

    The pound isn't worth what it used to be eight years ago, either:
    https://www.xe.com/currencycharts/?from=GBP&to...
    Reply
  • nivedita - Thursday, July 11, 2019 - link

    Noctua isn’t an American company Reply
  • logamaniac - Thursday, July 11, 2019 - link

    nor the pound an American currency Reply
  • Dug - Thursday, July 11, 2019 - link

    Nice to see a new cooler review. Hopefully more can come down the pipeline and get rid of the old coolers on here that you can't even buy. Reply
  • eastcoast_pete - Thursday, July 11, 2019 - link

    Thanks for the review. Two questions/comments:
    1. You mentioned the Evo212 in some paragraphs and a graph. I also believe that this is a good comparison cooler, as it also addresses price/performance. And, while the Noctua is a bit of a niche product, I would have like to see how it did compared to the higher priced "extra quiet" heatsinks shown. If you have the data, could you share them?
    2. I know that many people who are looking for that kind of cooler wouldn't care for whatever setup came with their CPU. However, those have the best price - free (with the CPU). It would be nice to know just how much extra thermal performance one gets by replacing the coolers that come with the CPU. May suggestion is to show the performance of the respective boxed Intel and AMD cooler alongside. With AMD making noise about their Wraith Spire cooler's performance (included with most of their desktop CPUs), I would really like to know just how much better these aftermarket ones are. Thanks!
    Reply

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