Quad-Screen Xinerama/Twinview weirdness

[John Nielsen]

On Friday 20 July 2007, Shaun Meyer wrote:
> I have been attempting to build a quad-display desktop using xorg,
> nvidia-driver-9331, nvidia-settings, and xfce4 out of ports on my fresh
> 6.2-release box.
> On the hardware side is one dual head nvidia agp card, and one (dual
> head) nvidia PCI (Geforce 4 Ti 4200 + FX 5200)
>
> My first impulse is to bypass twinview altogether and run them all on
> "Seperate X screens" in nvidia-settings with Xinerama.
>
> Upon X-restart the result is spectacular: Four introductory Nvidia logos,
> windows maximize like they should, etc, etc. Except performance is
> miserable and sluggish.
>
> When I change the configs around for two twinview screens, performance is
> great, as it is when I use just one screen except applications now feel
> like maximizing across two screens.
>
> How can I make this setup work properly?

Have you tried a Twinview setup_without_ loading Xorg's Xinerama module? 
(omitting any Xinerama flags or options in xorg.conf). The nvidia driver 
has its own Xinerama library but it can'e be loaded if Xorg's is already 
present. I've had good results with this approach using a single dual-head 
card, but haven't played with it much beyond that. Try it and let us know 
how it works out!

JN