Power consumption
We measured total system power consumption at the wall socket using an Extech power analyzer model 380803. The monitor was plugged into a separate outlet, so its power draw was not part of our measurement. We tested all of the video cards using the Asus P5N32-SLI SE Deluxe motherboard, save for the CrossFire system, which required a different chipset. For that system, we used an Intel D975XBX motherboard.

The idle measurements were taken at the Windows desktop. The cards were tested under load running Oblivion using the game's Ultra Quality setting at 1600x1200 resolution with 16X anisotropic filtering.

The difference in idle power consumption between the GeForce 7950 GT and Radeon X1900 XT 256MB is minimal, but a 60W difference opens up between the two while running a game. The gap widens to 100W when we switch to multi-GPU setups. Obviously, Nvidia's current GPUs are simply more power efficient than ATI's.