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 a loop of 3DMark05's "Firefly Forest" test at 1280x1024 resolution.

The CrossFire rig slots right in between the 6800 Ultra SLI and 7800 GT SLI systems, with NVIDIA's new generation of GPUs pulling less power than the older ones.

Noise levels
We used an Extech model 407727 digital sound level meter to measure the noise created (primarily) by the cooling fans on our two test systems. The meter's weightings were set to comply with OSHA standards. I held the meter approxiately two inches above the tops of the graphics cards, right between the systems' two PCI Express graphics slots.

Honestly, I didn't expect this result at all. The CrossFire rig comes out looking quieter than the GeForce 6800 Ultra SLI system. Subjectively, the whine coming off of the Radeon X850 XT cards seemed much louder and more annoying than the hiss of the fans on the GeForce 6800 Ultra cards. At least my impression that the 7800 GTs were the quietest overall was confirmed.