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 MSI card consumes around 18-19watts at idle, compared to around 14 watts each for the HD5770's. When gaming the GTX460 demands more power than both HD5770's, around 14watts. When we overclock the Talon Attack to 1ghz on the core the power consumption increases to around 160Watts, claiming an additional 15 watts over reference. Furmark demands 188 watts and 211 watts respectively from the Talon Attack, slightly more than the 201 and 204watts of the Crossfire solution.