The GeForce 9600 GT is based on a 65nm design, whereas the Radeon HD 3870 uses the even smaller 55nm design process.

This gives the Radeon HD 3870 a natural advantage when it comes to power consumption, and it did show, using 21% less power at idle while just 3% less when under load.

Interestingly, while the Crossfire Radeon HD 3870 cards use significantly less power at idle, they did consume more than the SLI GeForce 9600 GT cards under load. Keep in mind that the load results were recorded in Crysis and to a certain extent, the more effective the multi-GPU technology is, the higher the consumption levels are going to be.