As we have noted in our various processor reviews in the past several months, power consumption has quickly become an item of importance when looking at various PC components. The CPU and the GPU are by far the biggest single users of power from the PSU and your choices about which of these components you use will have an effect on what requirements you put on your power supply.
ATI has traditionally been the more power friendly GPU but that direction changed with the release of NVIDIA’s 7800 series of parts. Here we see that the CrossFire setup uses about 30 more watts of power at the idle stage and more than 80 watts more when we are in a full GPU load. These numbers are still less than the 6800 Ultra cards from NVIDIA’s previous generation of parts but the 7800 GTX is an outstanding value here if you are on a power budget. It performs nearly at the level of both dual graphics setup but at significantly lower load power consumption.