Power consumption
We measured total system power consumption at the wall socket using a watt meter. The monitor was plugged into a separate outlet, so its power draw was not part of our measurement. The idle measurements were taken at the Windows desktop, and cards were tested under load running Half-Life 2: Lost Coast at 1600x1200 resolution with 16X anisotropic filtering and HDR lighting enabled.

All of the graphics cards named below except for the two Radeon X1800 CrossFire setups were tested on the Asus A8N-SLI mobo. We were forced to use the ATI CrossFire reference mobo, of course, for the CrossFire cards. Thus, the numbers below are an indication of overall platform power consumption, but they encompass more variables than just the graphics cards' power use alone.

High-end multi-GPU systems aren't known for sipping power, and a pair of Radeon X1800 cards is no exception. The SLI systems require less power at idle, and the GeForce 7800 GT in SLI doesn't pull as much juice as the Radeon X1800 XL CrossFire under load. Nothing, though, eats up wattage like the dual GeForce 7800 GTX 512s in SLI, not even the Radeon X1800 XT CrossFire system.