We measured the power consumption of our entire test system at the wall while loading the CPU using Prime95's Small FFTs setting and GPU using FurMark. We also measured the power consumption with the system resting at the Windows 8 desktop. As this is a gaming system, we also decided to measure the power consumption while playing Battlefield 3.
Idle power consumption of 90W is what we would expect from a quad core system with discrete graphics card. A load power consumption of 285W shows that while this isn't the most energy-efficient system available, your electricity usage won't be ridiculously high.