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 AMD Radeon R9 Fury X topped out at 408W and the Sapphire R9 Fury X topped out at 404 Watts in the scene that we use for benchmarking in Battlefield 4. Not bad, but keep in mind that the Fury X uses a closed loop water cooler and has more compute units. Both are 275W TDP cards though.