Performance
Our benchmarks begin with the 105W AMD Ryzen 9 5950X CPU operating at stock speeds. We run the popular Cinebench R23 multi-core benchmark for an extended period and chart the average CPU temperature from the last five minutes of 100 per cent load.
We have tested the NH-U12S redux first in its default single-fan configuration and then with the optional NA-FK1 redux upgrade kit in a push/pull configuration. It is no surprise to find the affordable Noctua slotting in at the foot of the chart, but it is important to remember that it is up to 70 per cent cheaper than some of the liquid-cooled competitors, and still manages to keep core temperature comfortably below 70ºC.
Our trusty sound meter confirms that the NH-U12S is slightly noisier than a premium NH-U12A, but there's not a great deal in it. At stock settings neither cooler could be deemed aurally intrusive.
Upping the ante while maintaining complete stability, we raise the CPU multiplier to 45x on all cores and increase voltage to 1.25V. The modest overclock pushes CPU power up to 200W and represents a sterner challenge for coolers of this ilk.
With the overclock in place it is interesting to see the NH-U12S keeping pace with the NH-U12A, albeit with the optional second fan attached. Not bad at all, and the additional fan ought to be considered a luxury as opposed to a necessity.
Noise levels do begin to climb, however. The NF-P12 redux-1700 PWM fan may claim greater airflow, but it is more vocal in the process and tips the cooler past the 40dB mark. Interestingly, the NH-U12S in this scenario is quieter with the optional second fan attached; two blowers working in tandem don't need to spin quite so fast.