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 Coolers Testing Results
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  • Threska - Saturday, July 24, 2021 - link

    I think the larger point is that there isn't always an available choice. Sometimes the part we want is RGB or nothing. Not to mention the price could be larger for the RGB part. Reply
  • DominionSeraph - Sunday, July 25, 2021 - link

    The issue is that there *is* no style or fashion with RGB. It's simply bad taste. No girl is going to walk into a room with an RGB setup and drop her panties because the fans light up and the keyboard is cycling through the rainbow. RGB is in the exact same vein as a racecar bed or Batman pajamas. If you're beyond the age of 10 and your taste hasn't matured into something with just a *little* more sophistication, it's a sign that something went wrong with your development. Reply
  • Oxford Guy - Sunday, July 25, 2021 - link

    You’re paying for a feature you don’t want and other corners tend to be cut in terms of features you actually want.

    RGB stuff isn’t free.
    Reply
  • DougMcC - Thursday, July 22, 2021 - link

    I've never done a liquid cooled system. Could someone explain why the radiator on these coolers is designed to be mounted inside the case? Wouldn't it be drastically more effective if case makers designed for an external mount? Or am I just misunderstanding how you attach these to the case? Reply
  • meacupla - Thursday, July 22, 2021 - link

    Yes, the best results can be had when you mount the radiator outside the case.
    But the results aren't drastically better when compared to mounting the radiator to the case's air intake.

    Case makers tend to dislike external mounting of radiators, because buyers tend to want everything to be enclosed and look pretty. You would not only have the radiator dangling outside of the case, but you would also have the fan wires dangling out there too. It'll look like a cheap hack job.

    swiftech and koolance used to make an external mount bracket for radiators, but now that most modern cases, especially the really large ones, are designed to accept 2 or more internally mounted radiators, why would AIO CLC makers bother to make an external one?

    koolance still makes external radiators, but the cost on them is very high when compared to these internal AIO CLCs.
    Reply
  • DougMcC - Thursday, July 22, 2021 - link

    I see, thanks. I would think the dangling issues would be solved by having power delivered to the external radiator sleeved with one of the coolant tubes. Then you'd just have the pair of tubes into the case, and presumably the radiator top-mounted. Sounds like the cooling advantage isn't sufficient to drive adoption/standardization. Reply
  • Samus - Thursday, July 22, 2021 - link

    This cooler is a weird size at 280mm, so it's likely only going to fit certain cases that use 140mm fans.

    Silverstone has moved to 140mm fans after trying 180mm fans as far back as the FT-01 Fortress. The 180mm fans were garbage and seemingly an exclusive Silverstone thing. I've had multiple fail over the years where the bearing shaft detaches. Other failures people have noted on the interwebs have shown the entire fan shroud detaches from the motor or the motor support beams on the back of the fan housing crack at the motor mount, both causing the fan to 'knock' as it spins off-center and makes contact with the case, filter, etc. Very unfortunate.

    Anyway, basically the radiator attaches to the fan mounts of a case, with the fans mounted to the rear of the radiator. Some people do it the other way around, attaching the radiator to the fans. It depends what you desire for your cooling design (pusher fan vs puller fan) and some people do BOTH one in front and behind the radiator. The type of fan is an important consideration as well as most fans don't have high "static" pressure even if they are high RPM and rated at a high CFM. Static pressure traditionally isn't important unless you are trying to blow air through dense radiator fins, so sometimes the fan is more important than anything else, otherwise you won't remove much heat.
    Reply
  • Awful - Thursday, July 22, 2021 - link

    huh? 280mm using 2x140mm fans is absolutely one of the (3) standard sizes. Just about every AIO line comes in 240, 280, and 360mm... Reply
  • Threska - Thursday, July 22, 2021 - link

    Have a Silverstone going on ten years plus. All fans top and bottom still going strong. Naturally regardless of fan one needs to keep them clean. Reply
  • tonyou - Thursday, July 22, 2021 - link

    We haven't moved away from 180mm fans, in fact, we are still developing new models now. Engineering a fan with much heavier fan blade than typical 120mm x 25mm sizes was quite difficult as the rotational forces are exponentially higher. So material and bearing both have to be much stronger than typical 120mm/140mm fans. However, any external forces (such as debris or touching fan blade by accident) or slight tilt/angle enacted on our spinning 180mm also had significantly high risk of damage, so yeah, much less forgiving than smaller fans and that's why they may seem to be more fragile when in fact they are built better. With that said, we have been improving these 180mm fans over the years so the newer models and production batches should stand up better than their predecessors. Reply

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