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 measured the peak wattage used by the system while running the OpenGL benchmark FurMark 1.10.6 at 1024×768 resolution in full screen mode. We also ran four game titles at 1920×1080 and averaged the peak results recorded the highest Wattage seen on the meter for the gaming results.
Power Consumption Results: When it comes to power use the AMD Radeon HD 7990 6GB card did very well at idle thanks to AMD ZeroCore Power Technology. AMD ZeroCore Power Technology is designed to intelligently manage GPU power consumption in response to certain GPU load conditions by clock gating, power gating, memory compression, and a host of other power saving tricks. It also raises and lowers clockspeeds via AMD PowerTune and takes into account application use, system temperature and/or user system configuration. This is one of the reasons that all these high-end graphics cards have such good power numbers at idle!
At full load we noted that the entire system at the wall was pulling 546 Watts in game titles on average, which is about 100 Watts more power than the NVIDIA GeFroce GTX 690. The AMD Radeon HD 7990 6GB was more efficient than the ASUS ARES II as it used nearly 120 Watts less power when gaming. The ASUS ARES II, AMD Radeon HD 7990 and NVIDIA GeForce GTX 690 are all dual-GPU powered cards powered by flagship GPUs, so it shouldn’t come as a shock to see them pulling 450W and above when gaming. Just be sure to have a beefy 850W or higher PSU for your system with one of these cards.