I recieved my new cpu last week and can't seem to play unreal because of game speed ups and slow downs..
HP pavillion
AMD Athlon 64x2 Dual Core Processor 4200+ 
1.79 GHz
1.93  gigs ram
Nvidia GE Force 6150 LE 256 Shared
I went here and it didn't help
http://www.hardforum.com/showthread.php?t=983781

I have windows xp media center edition 

Any help would be appreciated i have a feeling its the dual core and not the video card and help or suggestions would be appreciated....