Game lags with 9600M GT and p8400

I recently purchased a Toshiba Qosmio F50-111, with core 2 duo p8400, 3GB of ram, vista and a 9600M GT.

I installed new drivers and bios, but when I play a left 4 dead or call of duty 4, games lags a lot and I have to go down the graphics settings at the lowest (while keeping the native resolution with 15" screen).

what I do not understand is that the PC of my friend (core 2 duo E2160 1.8ghz, 2gb ram, xp pro, 7600GT) run much better!

I do some research and found nothing that explains such low performance. (I think that can be integrated chipset running in place but not).

if someone could put some light on this better!

You play on AC or battery? you can check with the GPU-Z if your graphics card running at frequencies of reference when you play a game.

With 1200 x 800 resolution, and almost same configuration, I run Left4Dead at max and AA2X. You tried 179.28 drivers?

Incidentally it is the frequency of the GPU and CPU needs to be seen, maybe you have a problem with the PowerMizer (or software preinstalled forcing frequencies minimum).

Make a test with 3Dmark 2006. Also gpu-z for your graphics card.