Changing CPU Speed in System Properties?

[james2008]

I just noticed that the CPU speed reported by system properties in Windows XP changes periodically.

In the "Computer" section of the "General" tab, I see:

Genuine Intel(R) CPU
T2400 @ 1.83Ghz
987 Mhz, 1.00 GB of RAM
Physical Address Extension

The 987 Mhz sometimes says 1.83 Ghz, or a different number in the 900s. Can I improve performance by disabling speed changes?

In power manager, I have "Maximum CPU Speed" set to "Highest" when the computer is plugged in. There's an advanced option to disable CPU power management. Maybe that would stop the speed cycling? I rarely use my computer on battery power.

[Harryc]

In BIOS, under power options, Intel speed step, set mode for AC to Maximum Performance.

[GACrabill]

... The 987 Mhz sometimes says 1.83 Ghz, or a different number in the 900s. Can I improve performance by disabling speed changes? ...

That is Intel SpeedStep technology at work ... no need to run your processor at full speed, max power consumption, max heat generation, and higher fan speeds if you aren't really using the processor heavily at the moment (which for most of us is most of the time).

You will not notice improved performance by disabling SpeedStep ... you will notice more heat, more fan noise, and a shorter life expectancy of the fan (and maybe other internals).