Base on my experience installing windows 7 on Acer Aspire 4920G which use ATI Radeon X1350. Windows automatically install the drivers along windows 7 installation. After check for windows updates, windows also have a new updates for the cards and it is more stable.
INSTALLING USING ATI MOBILITY MODDER.
You can also use ati mobility modder which is available at http://www.hardwareheaven.com/modtool.php . I have a very long history with this site and it is one of the best site to get drivers or updates which is not available neither on manufacture nor official support site.
For performance, I myself love to test with different driver version. You can try Original vista drivers for example for HP 531use sp40783.exe.
To install you need to extract the driver and set the setup compatibility to windows vista. You can also install manually using device manager. I have a good result installing vista drivers for V3000 model compare using the latest drivers form nvidia.