CRYSIS high settings playing in a dell precision m6300 laptop

all settings hight postprocesing: medium 1280x720 dx9 i use a autoexec.cfg that inproves performance, but it dont change minimun fps, now i have 20-45+ in all the game, before put the cfg file i had 20-35 in all the game.i have only 20 fps when there are alot of action, and a very short time, i am using 181.20 and crysis goes a little bad with this drivers (i prefer 180.70 to play crysis) but now i am playing gta 4. the most of time 25-35 see the video in hd for best quality, i record it with my n95