Power Consumption
Our power consumption methodology is quick and dirty. It involves using a Kill-A-Watt device with only the test machine connected to it sans monitor and any external devices. The idle power is tested at the Windows desktop on a clean system while doing nothing but running background tasks. Load testing is done by using Cinebench R20 in a multi-threaded test. The power is then observed on the Kill-A-Watt instrument. These devices are not known for their accuracy, so this is a ballpark measurement. Cinebench R20 is largely used because it doesn’t utilize the GPU, which keeps the impact of the component to a minimum. All the systems we’ve tested from day one has been tested in this manner.
The CPU carries the same 95watt TDP as the standard Core i9 9900K despite the iGPU being disabled. It’s very strange that the disabling of the iGPU would make no difference here, but what we see at both idle and load is within a margin of error compared to the 9900K at the same clocks.
Overclocked, we see more of the same thing. The idle and load test numbers for the 9900KF are within one or two watts of the 9900K and therefore, don’t mean anything conclusive here. One would hope for a slightly reduced power envelope, but the fact is this iGPU is designed for mobile use where it needs to be as efficient as possible. Unless your doing something with it specifically, I don’t think it consumes anything substantial and these numbers seem to confirm that.
It’s important to note that the KF and K processor uses the same functional amount of power here as our 3900X, yet has substantially fewer cores and basically gets smoked outside of gaming benchmarks. Therefore, performance per watt is worse sticking with Intel.