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 system with the XFX Double Dissipation Radeon R9 290 installed used 119 Watts and idle and 453 Watts when gaming. Not bad performance numbers and it is within reason for high-end cards in the $400+ price range.