I have run some benchmarks, and my kill-o-watt is telling me that the system doesn't even draw 300W from the wall while gaming/ running gaming benchmarks. When I put together this rig, I was trying to keep heat output/power use as low as possible, so I guess that might have something to do with it, but it still seems odd to me.
My rig:
CPU: i5-4430 84W @ 3GHz
GPU: XFX DD 280x OCed @ 1150 mHz core 1600 mHz memory
Ram: 8GB Kingston 1.5V @ 1600 mHz
System drive: Sasmung Evo 250 GB
Storage drives: ~7TB of assorted drives (three hdds total)
PSU: Seasonic 650W Gold rated
Fans: 5 case fans (three from the Arc Mini R1 and two pulled from a Rosewill Blackhawk that was in a previous build)