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.
The Sapphire HD7970 6GB Toxic is consuming more power than the reference HD7970, around 275w with the ‘Lethal Boost' enabled when gaming. Sapphire have optimised this card for overclocking and performance so power consumption has suffered. We would have expected this anyway.