System power consumption was measured at the wall outlet using a Watts Up power meter. Load measurements were taken with Cool'n'Quiet disabled and the systems crunching a combined load of Cinebench 2003's rendering test and the rthdribl high dynamic range rendering demo. Idle measurements were taken at the Windows desktop with and without Cool'n'Quiet enabled. All motherboard components and peripherals were enabled, with drivers installed, for each test system.
Keep in mind that because our AM2 platforms are using an underclocked Athlon 64 FX-62, their power consumption results aren't directly comparable to our Socket 939 platforms.
The Radeon Xpress 3200 runs away with our power consumption tests at both idle and under load. However, it's worth noting that on both AM2 and Socket 939 platforms, the nForce boards have a greater number of peripheral devices and expansion ports. The nForce 590 SLI board, for example, features one more Gigabit Ethernet port than the Xpress 3200 AM2 platform and an additional onboard Wi-Fi card. Those extras are likely only responsible for a fraction of the 20 W power consumption gap between the Xpress 3200 AM2 and nForce 590 SLI, though.