CPU Cooler Test Methodology
CPU cooler testing is conducted using the bench defined below. We use a bench that is more carefully crafted for noise performance, opting for a passively cooled PSU and 23% RPM 980 Ti blower fan for very low system noise.
We strongly believe that our thermal testing methodology is among the best on this side of the tech-media industry. We've validated our testing methodology with thermal chambers and have proven near-perfect accuracy of results.
Conducting thermal tests requires careful measurement of temperatures in the surrounding environment. We control for ambient by constantly measuring temperatures with K-Type thermocouples and infrared readers. Two K-Type thermocouples are deployed around the test bench: One (T1) above the bench, out of airflow channels, and one (T2) approximately 2-3" in front of the cooler's intake fan. These two data points are averaged in a spreadsheet, creating a T3 value that is subtracted second-to-second from our AIDA64 logging of the CPU cores.
All six CPU cores are totaled and averaged second-to-second. The delta value is created by subtracting corresponding ambient readings (T3) from the average CPU core temperature. We then produce charts using a Delta T(emperature) over Ambient value. AIDA64 is used for logging thermals of silicon components, including the CPU and GPU diodes. We additionally log core utilization and frequencies to ensure all components are firing as expected. Voltage levels are measured in addition to fan speeds, frequencies, and thermals.
The cores are kept locked to 3.8GHz (x38 multiplier). VCore voltage is locked to 1.141v for the CPU. C-States are disabled, as is all other power saving. The frequency is locked without any interference from boost or throttle functions. This is to ensure that the CPU does not undergo any unexpected/uncontrollable power saving or boost states during testing, and ensures that the test platform remains identical from one device to the next.
Fan speeds are manually controlled unless otherwise defined. For liquid coolers, pumps are set to 100% speed unless otherwise defined.
No open bench fans are used for these CPU cooler tests. Only fans which are provided with the cooler are used.
|GN Test Bench 2015||Name||Courtesy Of||Cost|
|Video Card||GTX 980 Ti Reference 23% RPM||NVIDIA||EOL|
|CPU||Intel i7-5930K CPU @ 3.8GHz||iBUYPOWER
|Memory||Corsair Vengeance 32GB 2666MHz||Corsair||$175|
|Motherboard||EVGA X99 Classified||GamersNexus||$365|
|Power Supply||Enermax DigiFANLESS||Enermax||$250|
|SSD||HyperX Savage SSD||Kingston Tech.||$130|
|Case||Top Deck Tech Station||GamersNexus||$250|
|CPU Cooler||This is what we're testing!||-||-|
We use an AMPROBE multi-diode thermocouple reader to log ambient actively. This ambient measurement is used to monitor fluctuations and is subtracted from absolute GPU diode readings to produce a delta value. For these tests, we configured the thermocouple reader's logging interval to 1s, matching the logging interval of GPU-Z and AIDA64. Data is calculated using a custom, in-house spreadsheet and software solution.
Our test starts with a 180s idle period to gauge non-gaming performance. A script automatically triggers the beginning of a CPU-intensive benchmark running Prime95 LFFTs. Because we use an in-house script, we are able to perfectly execute and align our tests between passes.
pccooler W120 Isolated Tests
Let’s start with only the W120, just so we know what we’re dealing with for internal comparisons.
In full stock configuration, including the stock, age-hardened thermal paste, the cooler kept the CPU at about 60.7 degrees Celsius over ambient, which is one of the worst results we’ve ever recorded on this bench. Remember, this is without any radiators, and just a straight pump to and from the cooler. The stock fan is mounted to the finstack.
Replacing the thermal paste dropped temperatures by 6 degrees. As always with our cooling testing, this was conducted with three repetitions and averaged. The results were consistent with a 6-degree reduction against the included paste. For reference, we also have a photo of the cooler with the original paste after removal – you can clearly tell how hardened the paste has become. Curing will limit the thermal efficacy of this compound.
Back to the chart, a stock test with our standardized thermal paste had us at 54 degrees over ambient. Adding a Thermaltake 360mm radiator and three high-end fans – two Corsair MLs and one Noctua A12 – resulted in a reduction over ten degrees Celsius. This is more a testament to the fans and radiator than anything. Rising water temperatures required the extra cooling power directed straight at the liquid.
Noise normalized, the stock setup operated at 58 degrees, with the radiator version at 45 degrees.
Comparative Thermal Data
Moving on to comparative data with other coolers, the pccooler W120, using our controlled, standardized paste and no radiator, landed between an NZXT M22 120mm closed-loop cooler and EVGA CLC 120 at a lower RPM. This places the W120 as well below the X42 with a very low fan speed of 1050RPM, and also below the $90-$100 Corsair H100iV2 at low RPMs. The lower RPM limits cooling power of these coolers, but means that our noise levels are well below the W120.
Adding a radiator boosted us to H100iV2 performance when at 1500RPM, at 41 degrees over ambient for each. This is still unimpressive, particularly given the overall quality difference between them, favoring Corsair. The 360 radiator and high-end fans we equipped are being outmatched by cheaper coolers and worse fans, which means that we’re having trouble with cooling the coldplate. We’ll be opening up the cooler separately to investigate if there are even any microfins in the coldplate, or if they’re any good. We are bottlenecked at the W120’s coldplate and pipes for sure, though.
For our next test, we normalize all coolers to 40dBA of output, which ensures that we test on somewhat level footing versus noise output. Most people tune their fan speeds to tolerable noise levels, and so this allows quieter coolers to spin faster and cool better, while louder coolers will be quieted to meet our noise requirement. The result is a test of overall cooling efficiency versus a fixed noise level.
At 40dBA, the pccooler W120 without a radiator operated at the bottom of the chart, at 58.2 degrees Celsius over ambient. This is the worst device we’ve tested yet at 40dBA, and operates even behind 120mm closed-loop liquid coolers, like the EVGA CLC 120 and NZXT M22, which operated at 49 degrees and 54 degrees, respectively. The W120 is significantly worse for noise-normalized testing; although its fan pushes a lot of air, it’s loud and uses cheap bearings and plastic, and also proves turbulent through the finstack. This produces a lot of noise that could be avoided with a better design.
With a 360mm, fat Thermaltake radiator attached, using two Corsair ML fans and one Noctua A12 fan, the pccooler W120 operated at 44.8 degrees over ambient. At this point, the radiator is doing the bulk of the cooling, as our water temperature measurements indicated that the cooler doesn’t dissipate enough heat to keep liquid temperature low. More on this momentarily. With the radiator, the W120 starts costing beyond $200, but it performs about equivalently to a Kraken X42 140mm CLC and other $100 coolers, like the H100iV2 at 40dBA.
Water Temperature Measurements
Water temperature measurements were conducted with a K-type thermocouple placed within in the pump and reservoir combo unit from Thermaltake. This measured distilled water as it returned into the inlet from the cooler. Over time, we can see that the blue line, representing the cooler with no radiator but with our standard paste, slowly rises to about 36 degrees. The red line, representing the 360mm radiator test, only rises to 24 degrees. Note that ambient temperature was 21 degrees; we are not showing delta T values here, just straight temperature from the probe. We have adjusted with an offset as appropriate. Finally, the orange line, representing the original paste, illustrates that we have a clear problem with getting heat into the coldplate and getting rid of it effectively, where we rise almost linearly.
Noise levels at max RPM for the W120 fan place the cooler at 48.5dBA, equal with the X42 at max RPM. The X42 and other nearby coolers in noise are all superior in thermals, making this one a hard sell from any perspective.
Conclusion: pccooler W120
This isn’t something we’d recommend buying – plain and simple. It’s still really fun to work with, though, just because it is so weird and different. We’ll be doing a tear-down separately on the YouTube channel (likely in a livestream), so that’s where we’ll be able to better understand why the liquid cooling performance is so inhibited. It’s likely that there aren’t many fins in there, or no microfins at all, and that’s probably where the deltas come in. We’d still like to test this as a straight air cooler, but that’ll come later.
Editorial: Steve Burke
Video: Andrew Coleman