Closed Loop AIO Liquid Coolers: 14-way Mega Roundup Review
by E. Fylladitakis on February 12, 2014 7:00 AM ESTTesting 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, with the ability to vary the load, as the thermal resistance also varies depending on the magnitude of the thermal load. Therefore, even if it were 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 very 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 or compatibility. The thermal cartridge inside the core of our testing station can have its power adjusted between 60W and 340W, in 2W 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 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, we're measuring these manually. Fans can have significant variations in speed from their rated values, thus their actual speed during the thermal testing is acquired via a laser tachometer. The fans (and pumps, when applicable) are powered via an adjustable, fanless desktop DC power supply and noise measurements are being taken 1m 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.
| Noise Level Reference Values | |
| <35dB(A) | Virtually inaudible |
| 35-38dB(A) | Very quiet (whisper) |
| 38-40dB(A) | Quiet (slight humming) |
| 40-44dB(A) | Normal (humming noise, comfortable level) |
| 44-47dB(A) | Loud* (strong aerodynamic noise) |
| 47-50dB(A) | Very loud (strong whining noise) |
| 50-54dB(A) | Extremely loud (level equivalent to a ≈1500W vacuum cleaner) |
| >54dB(A) * | Intolerable for home/office use; special applications only. |
* Noise levels above this are not suggested for daily use
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E.Fyll - Wednesday, February 12, 2014 - link
It would not; even pure distilled water becomes conductive once it comes in contact with dust. None of these coolers are using pure distilled water anyway, all are using a mixture, which is conductive. It has lower conductivity than mineral water, yet it is conductive. The higher the portion of the additive over the distilled water, the more conductive the solution becomes. The actual level of conductivity also depends on the additive, some are more conductive than others. However, it should suffice to say that the least conductive additive at the lowest possible concentration would still be extremely dangerous to electronics.I will summarize: If it leaks, you are doomed.
Dustin Sklavos - Wednesday, February 12, 2014 - link
"If it leaks, you are doomed" is a little alarmist. It depends on where the product leaks and how large the leak is. The cooler itself certainly isn't usable anymore if it's leaking, but we get hardware in from time to time for leak damage that actually works perfectly fine (Corsair warrants your hardware against cooler leaks).E.Fyll - Wednesday, February 12, 2014 - link
Yes, I possibly over-exaggerated there. What I wanted to stress is that the liquid is definitely conductive, not that it will cause permanent damage 100% of the time. There is a high chance that the hardware will be damaged but that is definitely not always the case. I myself had a serious (nearly 1/4 liter) leak with a custom-made setup and the system was just fine once it was dry again.jrs77 - Wednesday, February 12, 2014 - link
Enermax and Silverstone use quiet possibly Swiftech as a supplier for their AIO-blocks.And btw, you should've really integrated the Swiftech H220 into your roundup.
E.Fyll - Wednesday, February 12, 2014 - link
I know. I actually tried to acquire all AIO coolers in existence, including Intel's, Thermaltake's and others. Not everyone is happy to cooperate and/or willing/able to supply samples at a give time, for whatever reason.toyotabedzrock - Wednesday, February 12, 2014 - link
We need a roundup of fans. I have bought many expensive fans that turned out to be less than advertised and failed quickly when used in certain orientations. Even had blades break.E.Fyll - Wednesday, February 12, 2014 - link
That is going to happen, eventually. I need proper equipment to properly test fans. Until I can acquire it, I will not perform a half-assed job.HisDivineOrder - Wednesday, February 12, 2014 - link
It's reprehensible that you guys are not reviewing the Swiftech option that allows you to use the closed AIO part or switch to a more open config if you like, too.If you say, "That's because it's not on the market now!" I'll say it's because of Asetek trying to basically own the market and are using litigation to destroy competition. Was it any wonder that when the Swiftech was on the market, we had Corsair and NZXT AIO's all dropping down to sub-$100 for even their highest of the high end? The value you got for that $130-140 was so outstanding, no one would touch a single one of these coolers.
So to my eye, I don't see why you'd bother reviewing such subpar products that are at ludicrous pricing and reward Asetek and their twin from another mother for not bothering to compete.
Not going to reward patent trolls.
E.Fyll - Wednesday, February 12, 2014 - link
Copy-paste from above:"I know. I actually tried to acquire all AIO coolers in existence, including Intel's, Thermaltake's and others. Not everyone is happy to cooperate and/or willing/able to supply samples at a give time, for whatever reason."
I cannot test what I cannot have access to. I would love to test Swiftech's products but the company needs to be willing to ship me samples first.
Dustin Sklavos - Wednesday, February 12, 2014 - link
"Reprehensible" is an awfully strong word, isn't it? There's a lot of logistics that go into just trying to put together a roundup like this, and respectfully, you don't have the full picture of Asetek's patent or what's going on in the AIO market.