I recently built a new desktop machine with the following configuration:
Mobo: ASUS Crosshair V Formula
CPU: AMD FX-8150
Graphics: AMD (Sapphire) Radeon HD 7970
RAM: Corsair Vengeance 32GB 4x8GB pack
My OS is Ubuntu GNU/Linux 12.04 with latest updates. For me, running Windows is not an option and I am not willing to do it anytime soon.
Unfortunately, after enabling antialiasing (set to override app settings in catalyst control center), I get very bad graphics corruption (random colored flickering pixels) all over the screen when using the GNOME3 Shell with fglrx/catalyst 12.2. The problem goes away when antialising is set to use app settings. For now, I can live without overriding antialias, but would be nice to know how to fix, or at least who to report bugs to.
By the way, the display's resolution is 1920x1080 and is connected using HDMI, if that is of any relevance.
I also tried running Debian testing/Wheezy with latest updates, but still getting same issue.
None of the hardware is overclocked/modified yet, but I plan to do it in the future when I see everything working.
From what I have seen, the problem might not be with gnome shell, even though Unity and KWin run perfectly fine with antialiasing overriden, because I have seen GNOME Shell run fine with antialiazing overriden on a laptop with Mobility Radeon with same version of OS and fglrx/catalyst and it also works on nvidia.
I haven't seen anyone complain about similar issues with the 7970 and fglrx 12.2 on the internet yet.
Does anyone else experience this? I want to know if I am the only one.