Power-consumption figures are pretty good when playing Call of Duty: Black Ops. AMD maintains that its PowerTune technology doesn't throttle the GPU speed when playing real-world titles. This is corroborated by logs from GPU-Z, which you can access here (txt file).
But PowerTune does step in to curb the power-draw when running an 'out-of-spec' application such as FurMark. The Radeon numbers look impressive, but the GPU isn't running at peak speeds all the time. Take a look at this text file and you will see that the Radeon HD 6970 flicks between a 598.5MHz core and the default 880MHz core speed.