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

Overclocking BCLK To 140 And 148 MHz

Wanting a real life situation to present, we decided to use the included Intel boxed cooler and marginal voltage increases. Users might want to boost system performance at little or even at zero cost, ideally without the increase in overall power consumption that significant voltage tweaks would entail.

140 MHz BCLK: 3.5 GHz Nominal Clock

Our first step was to 140 MHz, up from 133 MHz. This has little impact on the idle speed, but moves the nominal speed from 3.33 GHz to 3.5 GHz.

Turbo Boost goes up to 3.65 GHz when both cores are active...

...and to 3.8 GHz if only one core is being taxed.

148 MHz BCLK: 3.7 GHz Nominal Clock

Idle speed increases to 1,400 MHz with a 148 MHz base clock (9x multiplier). Nominal speed now is 3.70 GHz.

Turbo Boost accelerates from 3.7 GHz to 3.85 GHz when there is headroom to speed up both cores.

The peak frequency for a single core is 4.0 GHz now. Keep in mind that this all happens with only tiny voltage modifications (see the table on the following pages).