Ati 4650 lag

Do your other FPS games work the same as they were? If not, then reinstall your graphics drivers. If it's just with CF, then you might want to reinstall CF and if it's still the same, see if lowering the details will work (HD 4650 should be more than capable of handling CF), and if it still doesn't improve, then you're not alone...there's tons of threads where people have comps capable of playing COD4 maxed out yet they have crappy FPS on CF.