Early in January I put forward an article which highlighted the differences between the ‘ultra low voltage’ CPUs you get in Ultrabooks and the ‘low voltage’ CPUs you get in many laptops. I gave some comparison figures for two devices in different usage scenarios by measuring ‘system’ power drain and it was only in the high-end tests where we saw the ULV processor being significantly more efficient. In this article I continue the testing and compare the LV and ULV cores directly. The results are blow.
Measuring ‘system’ drain on two different systems isn’t the most scientific of tests so a discussion broke out in the comments about how we could measure a true difference in efficiency between ULV and LV processors and whether it could be possible to run low-voltage processors at slower clockrates and get the same efficiency as a ULV processor.
The theory says ‘No.’ If you run a CPU at the same frequency but with a higher voltage, the power usage goes up.