We've measured the power consumption during two scenarios: idle (where we determined an average based on 5 minutes of idling) and under load, where we measured the maximum power consumption during Cinebench 15.
Do note: from this generation onward we use a different (and extremely efficient) power supply, which means that the measured power consumption will differ slightly from previous measurements. We also configure the motherboards differently: everything is tested at default settings of the BIOS now.
In this test the X370GT3 does extremely well both in idle and under load. It's only a couple of watts, but in an ideal situation the idle power consumption would be slightly lower.