i got moving horizontal lines in CoD4 with the 8.3 driver too (CrossFire). my framerate was also about 1/3 what i usually get. i immediately tried to uninstall the driver, which didn't work. i had to go into the Device Manager to uninstall it. then i ran DC Pro and reinstalled 8.2. this is possibly their worst driver ever - hopefully they're working on a hotfix or patch right now.