This process removes the old drivers you were using and allows you to put newer ones on your PC without any of the old files causing any havoc,
You should do this because the card you are using is 2 (1) generation newer.
The drivers currently in your machine are not optimized for this card.
If you have removed the old drivers then installed the new ones that came wit your
new card, it is likely some files were left behind and the steps above will help you resolve the issue.
i have done that... but to tell i was playing Dragon age 2 Dues Ex human Revolution... duke nukem Forever are playing perfectly alright ranges between 50-60fps... but with gta 4 crysis, blackops.. its just a ***
So you used driver sweeper then restarted ? after doing so you downloaded the latest or at least driver package 11.3 (even 10.4 is fine) I use them both using two different hard drives. I should work or perhaps you are using an adapter instead of a 6 pin pic3 cable this can cause issues ps do not let windows install anything related to the AMD card