Overclocking, Power & Thermals
For Power usage, we will be using a FLIR CM78 DC Amp clamp directly monitoring the 12V EPS connections to the motherboard. This gives us a real-world accuracy of +/- 2 Watts across our entire measuring range from 0W to more than enough to melt both 8-pin EPS plugs.
Out of the box, the Core i9-10900K runs at up to 5.2Ghz on 2 cores, or up to 5.3Ghz if cooling permits via Thermal Velocity Boost.
Thermal Velocity Boost ONLY applies these increased clocks to the two best cores, selected by Intel at the factory and denoted in red in CPUID’s latest CPU-Z tool. In our case, this happens to be Core 8 and Core 9 (or 9 and 10 if you start counting at 1 instead of zero).
From there, we see 5100Mhz with 3 cores active, 5GHz with 4 or 5 cores active, and a still impressive 4900MHz with 6 to 10 cores active.
At stock, we see temps hit a tepid 68C on the hottest core. This is 10 cores, at 4.9Ghz folks. Less than 70C! the new thin die and Solder Thermal Interface Material is doing its job and doing it well. When we first tested the i9-9900K, we were in the mid to upper 80C range here. More cores, more threads, faster clocks, and significantly cooler temps. We’ll take that any day of the week!
Voltage is reading about 1.224V here, so that has a fair amount to do with it. You can try to bash Intel for re-using the 14nm node yet again, but it is WELL refined at this point. Power usage lands at a pretty hefty 246W though. Remember that TDP is THERMAL Design Power, NOT actual power usage.
From here, we’ll bump the multiplier up to 51 on all cores. We get a nice jump in performance, with a modest jump in voltage to 2.84V which gives us temps landing around 80C on average with the hottest hitting 84C. You can clearly see our two good cores here sitting at 71C and 75C. Power draw jumps to 308.4W under load.
At 5.2Ghz on all cores, we are starting to bump thermal limits, with the hottest core hitting 96C and the package bumping the 100C limit. Power jumps to nearly 380W at this point and the voltage has to come up quite a bit to keep it stable under AVX loads. With a little lengthier fine-tuning, this can probably be trimmed back, but 5.1Ghz on 10 cores is a pretty killer system as it is and 5.2Ghz is certainly doable.