Does anyone know how well this is supported?

I currently run 2 nvidia cards and xinerama them for three 1920x1152 monitors to one desktop. However, xinerama is beyond bad and the performance is miserable with random occasional system freezes. As far as I can tell, all the 4+ output nvidia cards at best do twinview in pairs, i.e. for 3 monitors xinerama is still required.

Just wandering if its possible yet to get one of the 3+ output ATI cards with Eyefinity and get 3 monitors working as 1 desktop with reasonable performance (i.e. can drag a window or use a scrollpane...)

Thanks for any help,