To test power consumption today we are using a Keithley Integra unit and we measure power consumption from the VGA card inputs, not the system wide drain. We measure results while gaming in Crysis Warhead and record the results.
The results are close to those we recorded with the HD5770 in the past, peaking at under 90watts when gaming. This is a rather efficient design with two cards only demanding around 170 watts under load.