low fps

i just got a new asus g60vx and only get around 15-35 fps with gamebooster.

specs: intel core 2 duo p7450 @ 2.13 ghz, 4 gb ram, x64 bit, 1 gb dedicated memory for geforce gtx 260m, windows 7

i've tried different compatibility modes and was unable to change the priority level of crossfire.exe in the task manager.

why is it that i can play modern warfare 2 fine on high settings but only get an average of 25 fps on crossfire with gamebooster? any suggestions?