Power Usage and Temperatures
For power testing, I hooked each of the test configurations up to a Kill-A-Watt and documented complete idle numbers then loaded the CPU up to 100% with wPrime for the load numbers. Unsurprisingly the 140W TDP i9-7900X was up close to the top of the charts at 226 watts but the idle numbers weren’t too bad at 66.9 watts. The i7-7740X wasn’t as bad with a slightly lower idle number but the load at 123 watts was MUCH lower.
For temperature testing, I retested all of the CPUs in this review using AID64’s stability tester with just an FPU load to heat things up the most. Now remember these numbers aren’t perfect, you have to rely on unreliable software/in CPU results combined with things like AMD adjusting the numbers by 20 degrees as well. That said I included them all just for reference. The i9-7900X didn’t do too bad with a peak of 58 degrees using the Noctua cooler but the i7-7740X, like the i7-7700K didn’t do very well. If I were just using these numbers I would guess that the 7740X was using TIM under the heatspreader and the 7900X was soldered, but everything (pre-launch) is saying that both will have TIM so I’m not sure why it would register so much lower beyond untrustable software based testing. SO take these numbers with a grain of salt right now.