8178 / 2 FX5200 / 4 heads / slow

[mw171]

Hi,
I am using 2 FX5200 with 4 heads in twinview mode with xinerama with good
performance. My problem is that the windowmanager (icewm) thinks of 2
screens with 2560x1024. So any "fullsize" operations grows a window over 2 screens. That's not very usable. So I tried to configure X with 4 screens without twinview. The effect was a very bad performance. The load increases. Any window move, resize or focus change is very slow.

Is there anything I can do to have the same performance with 4 screens in no-twinview as in twinview mode?

Thanx!