Efficiency Explored: What's The Perfect Clock Rate For Your Core i5?

Benchmark Results: Power Consumption

Slight increases in the BCLK frequency do not have a noticeable impact on the overall system idle power. All three settings (133, 150, 160 MHz) result in the same 71W reading. This is good to know and have, as the final Turbo Boost speeds go much higher—when they’re really needed.

The fastest setting at 4.2 GHz could only be reached with power saving options disabled. This has a terrible impact on idle power. The 50W difference is sufficient to run an additional 24” display or two powerful graphics cards in CrossFire or SLI mode.

These numbers reflect the system power consumption at full load using all four cores. As you can see, the overclocks with Turbo mode enabled result in only slightly increased peak power. Going from 155W peak to 164W peak is very acceptable, considering that the maximum clock speed now reaches 3.84 GHz instead of the former 3.2 GHz. That’s a 20% clock speed increase (for one to two cores) for only 6.5% higher power consumption.