Unreal tournament 3 low preformance

A friend of mine just recently purchased a laptop to play games because he was tired of breaking down his desktop for lan parties. I recommended him an ASUS with P8600 (2.4 ghz core 2 duo 1066mhz fsb) 4GB ddr2 800 Nvidia 9800m gs.

I was expecting him to be able to run unreal tournament 3 without any problems at all, but the framerate will run in the high 80's to 90's for 3 or 4 seconds and then drop down to the mid to low 30's for a second or 2; then it repeats. If it would just stay at the higher framerate, it'd be fine, but it seems something is not right with it. It doesn't seem to matter what resolution the game is played at either and I have dropped the eye candy down to "1" for both graphics settings. It seems this is a CPU bottleneck, but his cpu should be plenty good to play the game. Even my old 3800+ x2 was fast enough to play the game at high 40's even in the most difficult maps.

He is running vista 64 home premium. is it possible the 64 bit OS is slowing things down?

I'm up for trying anything to keep framerate up above 60 at all times.

his graphics driver is up to date. I tried updating the chipset drivers, but the one they had online was older than the one on his laptop. I couldn't think of anything else to update than those two.

the new Nvidia driver(8.12) is very buggy i recommend rolling the driver back to a version 7, and giving it another shot.