I am a fan of AMD over long time and currently have a 290x graphics card.
I recently invested in a dream of monitors, being the famous PLP setup of 30" 2560x1600 flanked by 20" 1600x1200 in pivot. This is an awesome setup!
I have found out that you don't support eyefinity in PLP setups (though it beats my why and how hard it can be) but probably will do it with 285 graphics card, though that would be a downgrade for me. I also managed to completely mess up my screen settings by trying eyefinity so I had to wipe my harddisk and reinstall windows to get them sorted again even though I disabled eyefinity and tried all kinds of driver cleaners. But that is a different story...
So since eyefinity won't work I have seen many examples of people spanning games across the screens simply by running windows in 4960x1600 resolution and it works great, though CF won't work. However all these examples are done on nVidia cards where they set a custom resolution in the control panel of 4960x1600 so they can choose this resolution in the games.
My games refuse to go any higher than 2560x1600 (the native of the central screen) even in windowed, but I can move the window just fine around the screens. I just can't make the window itself bigger than the central screen. I have tried to use the "custom resolution" in the AMD panel, but first of all I can't go higher than 4096 horisontal (so not 4960) and second it refuses to set because it insists on "validating" the resolution first. Well I know it won't work on the one screen, but I need it to be registered in the system so I can pick it in games running in window mode.
I also try running games with command-lines, but again they will go down to central screen resolution and refuse to pick the higher resolution.
Quesion: How do I register my 4960x1600 resolution on the AMD card? Will I have to purchase a nVidia card to make this work (since all videos and guides online refer to this being "no problem" but all are run on nVidia cards). I would hate to part with my 290x, but if that is the only way...
And on top of this when will you support PLP setups in eyefinity? The setup has been popular for many many years now...