There are also many people with this problem!! Look at this website!
Don't know if it's the same problem or not.. but this problem from this website is from year 2005!!!!
Anyway In Year 2011, I am facing this problem after getting my first AMD CPU based laptop..
I have found out that although it's advertised as 2.2Ghz.. it's only running at 800mhz!!!!
So I did an experiment. Go to bios and disable powernow!
AFter disable Powernow! see the result!