Clarkdale Efficiency: The Perfect Clock Rate For Intel's Core i5-661

Benchmark Results: Power Consumption

Idle power depends on the processor’s idle clock speed and applied voltage. Once we started to increase the processor voltage, we saw an increase in system idle power as well. The idle clock speed went from 1,200 MHz for the 3.33 GHz/133 MHz BCLK default setting to 1,440 MHz at 4.0 GHz/160 MHz BCLK. However, 40W instead of 35W sounds acceptable in the light of the performance gains.

Peak power also increases from 86W at maximum clock speed (3.46 GHz) to 114W when running 4.16 GHz. That’s quite a bit, but keep in mind this only applies under heavy load, and that the CPU goes back to idle state once open tasks are completed.