Test Results: Idle
Both minimum and minimum average numbers are taken and calculated from measurement results five minutes after booting. The system is idle at this time, though some spikes of activity still occur.
Athlon X2 7750
The results are very interesting indeed. As noted before, running Cool'n'Quiet with the Windows power policy set to “Balanced” offered minimal savings. It’s only when we change the voltage that we're able to significantly save more power--about 13 watts lower consumption, or a total of 20 watts compared to running without power management. That's a savings of 25%.
Athlon X2 7850
The Athlon X2 7850 exhibits a different behavior, more likely since it correctly applies a lower voltage when Cool'n'Quiet is enabled. Enabling Cool'n'Quiet saved around 13 watts, and lowering the operating voltage for both the processor’s p-states saves us an additional 9 watts (total savings are 22 watts, or 22%).
Athlon II X2 250
The Athlon II X2 250 is probably the least power-hungry processor in AMD’s entire lineup; it's certainly the least power-hungry of the CPUs we've tested here. With Cool'n'Quiet enabled, system power consumption with this processor is much lower than the Athlon X2 7750 or 7850. With tweaked voltages, you can see even lower levels of consumption. We went from around 76 watts with no power management to 72 watts with Cool'n'Quiet. We even saw 63 watts when we tweaked the p-state voltages.
Note: on the new Socket AM3 platform, we were able to go well below the numbers above. Idle power consumption drops to 39-41 watts when undervolted. That's quite a jump, even when compared on the TA790GX 128M, which sits at 50 watts idle.