fpshelp

Ive just replaced my tnt2 pro with a geforce mx 420 and my fps went from good to poo. I mean...on cs i used to be able to play any map with about 50-60 fps with no lag what so ever on the maps, but now i get better fps (i touch 99.9 in some places ffs) but in alot of areas they poo down to 20-30...