As with our SBM systems, power-savings options were turned off in the BIOS, and Windows Vista’s power-savings feature was set to High Performance. Let’s take a look at the total system power usage measured from the AC source. We’ll include a chart for the Radeon HD 4870 and a second while using the Radeon HD 4870 X2. Keep in mind that the Athlon 7750 uses a different 650 W power supply than the other three processors do. But again, both PSUs share similarities and are rated by Antec with up to 85% efficiency.
At stock speeds, the Phenom II X3 720 BE consumes the least power in each test. Once overclocked and running at full CPU load, it consumes about the same amount of power that the Athlon 7750 does. Without turning on power-saving features, the Phenom IIs clearly offer quite a bit more bang per watt than the previous-generation AMD processors.
Idle consumption doesn’t go up all that much with the Radeon HD 4870 X2, but under load we clearly see the increase in 3D performance doesn’t come without a substantial increase in energy consumption.