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.
The Zotac GTX460 AMP! consumes around 3 watts more than the reference card when idle and when gaming this rises to 153 watts, around 30 more than the reference board. When running Furmark, we see the power consumption peak at around 190 watts.