After previous unsuccessful attempts at getting Mandriva to work woth multihead video cards, now that my Windows installation is regularly blue-screening, I have given it another go with the latest version. Now it is nearly there, although it wasn't a painless installation (only one monitor worked and I had to dig around the net and manually alter my xorg.conf file to get all the monitors going).
With the Matrox G200 I have four displays working. But only in 16 bit colour depth and only at limited resolutions.
Up to 1152 x 864 screen resolution is fine.
If I go over that (1280x960, 1400x1050 or 1600x1200 are the ones I tried) or try 24 bit colour depth at 1024x768, the primary display is corrupted although the other three displays are fine.
The corruption is in the form of random horizontal lines, interference where the mouse cursor is or was, somtimes lines copied from other bits of the screen.
Can anyone suggest what is causing this as I really want to fix this to run both higher resolution and higher colour depth. If I can't fix it then it might just be enough for me to end up having to go back to Windows :-(