Yesterday we got this email from Matt Bentley:

Changing Microsoft XP power scheme settings determines whether or not power-saving CPU features are activated in a machine when idle.

All modern desktop CPU’s past the AMD Athlon XP and the Intel Pentium 4 (ie. AMD A64 & Intel Core and upwards) have some kind of speed-stepping feature built into them, which is utilised via Windows XP’s power management settings as per Orthogonal Thought’s blog.

What does this mean? Well, basically, if we all switch our desktop computer’s power scheme to ‘Laptop/Portable’, our computers will drop the cpu voltage and frequency when idle (provided the motherboard supports it, and most do), saving 30w (on average) - it’s like switching to an energy-saver lightbulb, essentially – and has absolutely no performance impact when not running idle.

Learn more: Intel SpeedStep, Windows XP, and confusing Power Profiles