overclocking e7200

[bugabooz]

Hey, Trying to over clock my e7200 a bit. I tryed the 10% auto overclock and it booted up fine. I ran 3d mark06 and got just over 11,000 when i used to get 10,500. But then i tryed extracting a 4.5gb movie with winrar having the cpu overclocked caused it to take 30 seconds more. Does the auto overclock function not work properly? Or is there something im missing. Also the temperatures that PC Probe displays only change by about 2 degree's when I do a 20% overclock. Could the temperature sensors not be working properly? Thanks