Using a xeon e3 and a powercolor 6870 eyefinity 6 I have successfully gotten 6 24" monitors to display in centos 6! The whole process was mostly trial and error as the amd control panel is a bit flaky. I ended up installing a few different distros until I found one that played nice with the hardware (redhat 5.7 was a huge hassle and never worked).

However, moving windows is very slow. Windows move across the screen about 1 FPS even though the mouse doesn't have much lag. Are there any ways to speed this up?

Also, there is quite a bit of flickering on monitors 5 and 6. Currently they are connected via DVI cables though all monitors have displayport inputs. I have ordered 2 more displayport cables and hopefully this will eliminate the flickering as I'm thinking the culprit is DVI.

But still the speed is so slow. If I were able to fix that I'd be rockin!