Hello So I own a Dell Latitude D531 laptop. I been planning to use it as my back up laptop if my main one goes down. The only thing that was replaced was the motherboard and the battery, I replaced the motherboard because I bought it form a High school and it had a bios password and the seller didn't know what is was. After the replacement I installed windows xp 32bit and all the drivers. but I noticed an issue that the cpu will run at 798mhz if I reboot it with out the dell charger plugged, and it will run at 1.60GHZ instead of 2.0GHZ if I reboot with the charger plugged in. So I thought it maybe the AMD Power Now! feature causing it so I turned it off in the bios. It did help some windows still shows that it running at 798mhz but when in cpu-z it shows that it running at 1.9ghz. So I proceed to go to you tube and watch a video since that what it will be doing mostly. video starts runs smooth at 480p then it started to stutters so I open cpu-z and it was running at 798mhz then like after 30 secs it will go back to it correct speed and it will Continue to do that if I don't plug in the charger if I remember correct. The cpu temp is around 45-54c and will still switch between 798mhz even when it at 45c. Have any idea what is causing this? Is it the board? Or is it the cpu? the cpu is a Turion 64 TL-60.