[HELP] Laptop problem

Hi guys, i bought a laptop: HP Pavillion dv6-1330sp, which is very good! It has an ATI Radeon HD 4.6 gb ddr3.
So, i should always have 100fps, but i have not ! i know i should put this in the FPS default thread, but i believe this is just a bad configuration or something.

So... the computer is very good, and when i play CS, i'm 100 fps and suddenly, it drops to 30/40...
I changed the graphic card setting from high quality to high performance, and now it drops to 70/80, but even so, this souldn't happen

Anyone can help me? by the way this is and windows 7 system.