I don't know which distro you use to tell you more specifically. But if you have and HD2xxx-4xxx Radeon card, 12.4 was the last to support it, but there is the legacy 12.6 driver too(exzclusively for this unsupported hardware) which I'd suggest you use ( also supports xorg 1.12 ). I didn't have any artifacts for sure from 12.4 onwards, but from 12.6 it was better and fixes for Gnome Shell were in the changelog
Hope it works well for you if you try it. I think it would.