For testing power consumption, we took our test system and plugged it into a Kill-A-Watt power meter. For idle numbers, we allowed the system to idle on the desktop for 15 minutes and took the reading. For load numbers we ran Battlefield 4 at 3840×2160 and recorded the average idle reading and the peak gaming reading on the power meter.
Power Consumption Results: The XFX Radeon R9 390 Black Edition was on the higher side of things when it came to power consumption. We found the system used 108 Watts at idle and 448 Watts at peak gaming with the Radeon R9 390 8GB video card installed. The Zotac GeForce GTX 970 AMP! Omega Edition video card used 104 Watts at idle and 292 Watts at load, so the comparably priced card from NVIDIA uses more than 150 Watts less power when gaming with regards to peak numbers.