We used a calibrated meter to measure the power at the wall. No monitors were factored into the readings. The system power drain was measured in the following states:
Idle: when resting at the desktop.
CPU Load: Cinebench R11.5 64 bit benchmark run.
Gaming Load: 3Dmark 11 ‘combined test’.
The system is actually relatively efficient, considering the overclocked state. When under gaming load it consumes around 350 watts of power.