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. The best way to get maximum load results is by using Furmark, and even though it is not indicative of a real world situation it shows the limits the card can theoretically demand. The ‘gaming’ results are measured when playing Crysis Warhead and is a more valuable result to take from this.
If you plan on running the HD6970 in 3 way CFx then be prepared to upgrade the power supply. The demands are high, to match the stunning levels of performance.XFX HD6970 3-way CFx & HD6950 CFx review,