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 7 desktop. As this is a gaming system, we also decided to measure the power consumption while playing Battlefield 3.
Idle power consumption is very good at less than 100W. This is largely thanks to AMD's effective ZeroCore technology implemented in the Radeon HD 7850 GPU.
As the load increases, power consumption rapidly increases to a maximum of 355W which is high for a system of this calibre. OCZ's ZS Series 750W PSU won't struggle with the task of powering this system – you could even add an additional Radeon HD 7850 graphics card without power-related problems.