Results: Power Consumption And Efficiency
System idle power remains basically unchanged even if you increase processor voltage and clock speed. The processor’s power management is capable of keeping the processor at top power efficiency by shutting down units and cores when not needed. However, we had to switch off the C-state management to reach clock speeds faster than 4 GHz, and this had a significant impact on system idle power.
The difference in peak power is similarly noticeable. Power consumption almost doubles when going from 2.66 GHz to 4.2 GHz. Apparently, the resulting performance isn’t twice as high, meaning that system efficiency might suffer quite a lot from the overclocking.
Predictably, the standard clock speed with Turbo Mode enabled provides the best power efficiency (performance per watt). Increasing clock speed and voltage the old fashioned static way results in increased performance, but even more increased power consumption. Anyone looking for an efficient machine should refrain from massive overclocking.
