The Noctua NH-U12S Redux is designed for Intel Socket LGA2066 / 2011 / 1200 / 1156 / 1155 / 1150 and all modern AMD processors. Here is an overview of the system and testing methodology
ASUS Maximux XII Hero – Z490 Chipset
Intel Core i9 10900k (3.7Ghz) Deca Core 10 x 32KB L2 Cache 10 x 256KB L3 Cache 20MB
Noctua NH-U12S Redux
Cooler Master Hyper 212 RGB Black
The CPUID System Monitor was used to obtain and record system temperature data and being that this is a quad core processor we need something that will work across all of the cores at once. For this task we're using a new version of Prime95 (p95v255a) that will allow you to spawn (n) instances to test with.
Editors note: Even though the Windows 10 task manager reported 100% processor usage we could never attain a 100% of the rated heat output as documented by Intel when using Prime95 as a basis for that heat production. Knowing this we ran the stress test until the maximum temperature was attainted and stabilized.
Other things to consider when judging software induced heat output.
a) Clock throttling by the processor at high temperatures.
b) Normal software isn't designed to produce maximum heat output.
c) Variances of cooling temperature.
d) Variances in CPU load.
e) Inaccuracies in thermal diode readouts.
Of course the list goes on..
Our testing methodology is aimed to provide a real world look into this heatsink given the test system provided.
A C/W rating can quickly be calculated using this formula.
C/W = (CPU temp - Ambient temp)/(Variance(%) * CPU Watts)
Allowed variance for this test = 85%
CPU Watts = 125W (or 137W due to turbo clock)
0.30 C/W = (59C - 24C)/(.85(137W))
For this next test I typically overclock the CPU and run the thermal test again. However, Comet Lake isn’t a good overclocker and instead I decided to modify the fan curve to be a little more aggressive and something I would normally do when aircooling on a gaming rig.
The thing with fan curves is that they respond to temperature and are intended to provide adequate cooling while also minimizing noise. This has a side effect of also dictating what the final temperature number will be. Simply put if the fan goes 100% at 50c then the CPU temp will likely be 50c or less, going beyond 50c will saturate the cooler and you’ll have a bad time.
A new C/W result for this test.
0.26 C/W = (55C - 24C)/(.85(137W))
In our heatsink and waterblock tests we don't really focus on overall load temperatures but rather how well the product can remove heat given a specified heat load. Since this is a real world testing method we need to take into consideration real world variables and estimate tolerances. This is why we normally only apply 85% of the total wattage output to our heat calculations.
The resulting C/W number is used to rate how efficient a heatsink or waterblock is based on the given heat load. These numbers can be used to determine heat capacity, the larger the difference the less efficient the heatsink is. (aka not good for overclocking)
As the charts show we have a heatsink that can clearly handle the Core i9 10900k and while I didn’t include any real overclocking numbers, I did tweak the fan curves to show a potential for the cooler if noise was not a factor. For the secondary tests the fans were almost topped out at 1660 RPM and offered a 3 degree drop in load temperature which also lowered the overall C/W.
Keep in mind these calculations are provided for demonstration purposes only and may not reflect the actual lab tested C/W rating, but we're pretty close.