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.
In such an energy aware climate, AMD are making a big deal out of their new ‘ZeroCore Power’ technology. Many solutions today use power gating, clock gating and memory compression to reduce idle power requirements, but ZeroCore power technology can completely power down the core GPU while the rest of the system remains active.
Each card demands approximately the same as other HD7970's we have tested, which isn't a surprise as these are reference based cards.
We attached the system to a power meter, to get a reading of the power drain under load when running 3DMark 11. These results are actually very impressive, considering we have three HD7970's running inside a liquid overclocked Core i7 system.