You can try cutting down on running processes using MSCONFIG.
Making your pagefile static.
Defragmenting.
Using disk Clean.
A registry cleaner such as Regseeker.
Make sure windows is up to date along with the game patch and direct X/video card driver.
Other than that, Im curious as to what process in task manager is eating so many cpu cycles. So maybe you can post screen shot of it after a game or just tell us.