I only see AMD Adrenalin drivers for Windows and Linux operating systems. But I found this in a search:
Click the Apple logo. On the "Apple" menu, click "Software Update." If there is a Mac OS X update available, you can install it. If there is a graphics driver update, it will be included in the Mac OS X update.
As Albert Einstein said, "I could have done so much more with a Big Al's Computer!".