Power Usage and Temperatures
With the move to what Intel calls Intel 7 or the 10nm manufacturing process it does mean there is some potential for improvements in power usage. But Intel's old tick-tock launch cycle was more likely to have those and that has been gone for a while now. To take a look at power usage I ran three different tests. I noted the idle power draw of our entire system then I took a look at the load wattage of the system using two different workloads. One was wPrime and the second was AIDA64 using their FPU workload which is extremely demanding. Before diving into these results I should point out as I mentioned earlier that our testing of these CPUs did have the PL1 and PL2 power limits turned on at 250 for the i9-12900K and 150 for the i5-12600K and those won’t/don’t come limited at all on most gaming and higher-end motherboards. For reference when I did some initial testing with the 12900K uncapped our test system with the FPU workload was pulling 430 watts. With the cap in place, the 12900K based system pulled 364 watts which is still a lot but much better than when things were uncapped. This put the 12900K right with the older 10900K and overall it is clear that the gains that the 10nm gave were used for performance, not to lower power usage. The 12600K was better at 227 watts with the FPU workload but this was higher than the 11900K with MCE off from last year that it performed close to in a lot of tests.
As for idle power usage, I thought I would see better power usage here with the new e-cores but that wasn’t the case with the 12900K at 78.8 and the 12600K at 78.3 watts. That was even after I went through and made sure none of the programs running were causing problems and I found that iCue for our cooler was causing both CPUs to use an extra 20 watts. The wPrime workload had MUCH better wattages, but if we remember back to how both CPUs performed in wPrime we know there is an issue there with how it handles the e-cores.
I also took a look at temperatures. For all of the CPUs tested below we were using a 240mm AIO cooler. You can see that the higher power usage was heating things up as well. The 12900K was running at 88c and the 12600K was much better at 63c. When you don’t have the PL2 power limit set, both were running at 100c, if for no other reason than that. I would highly recommend making sure you have that set to a reasonable number unless you are looking to overclock.