Originally posted by mouse
My solution would bne to open it up and look, a P3 500 will be rectangular with its heatsink pointing sideways, a P3 1GHz will be square and pointing upwards, probably with fans on - which my old P3 500 didn't have.
That isnt always true there are slot 1GHz P3s. I have one; the workstation board that i have uses slot-based only with rimm.
If it is a notebook:
Then when you look in the properties, do you have it plugged into AC power? If not, its because of the power consveration firmware in the computer. It trades of cpu speed for battery life. AMD calls it "Power Now!" and Intel calls it "SpeedStep".
But once you plug AC power back in, the CPU speed should go back to normal.