TwinView/Xinerama performance issues on 3 screens

[urbanslayer]

I'm running a 2x GFX cards, 1 AGP 6800GT and 1x PCI 5200FX. I have gotten all 3 screens running in a combined mode using either TwinView or Xinerama. Im using Ubuntu Hoary which comes with Xorg and the latest nvidia drivers.

However, under Xinerama, the performance is awful, very very slow to redraw windows etc. Under Twinview on 3 screens (2 using TwinView, 1 using Xinerama), the TwinView'd screens span video etc over both of them, whereas if i dont have the 3rd screen active, they dont (a full screen video will only full screen to one screen, which is what i want). I have read the ReadMe with the driver, and it does mention about using Xinerama and TwinView together will cause certain problems with TwinView etc, and I can only assume this is one of them.

Is there anyway to either increase performance under a Xinerama screen setup, or prevent applications etc spanning 2 screens with TwinView & Xinerama?

I have tried the NoTwinViewXineramaInfo option, but this has had no effect.

Can anyone help?

[Alex Cavnar, aka alc6379]

I would have to go out on a limb with this one-- it might be something with the nvidia driver you're using.

The only thing that I could possibly think of is turning off Xinerama, and just using each head as another display: :0 for one, :1 for two, :2 for three, and so forth. That's about the only way I can think to permanently keep a window from spanning two monitors. Disabling Xinerama is as simple as commenting out the line in your XF86Config or Xorg.conf file and restarting X.

[urbanslayer]

I have now kindof sorted it. The main app I was most bothered about was Mplayer, since it made videos look very stretched as it was putting them on 2 screens (even when it wasnt fullscreened). I have now since found a config option to force it to one Xinerama screen, so when it maximises, it only goes on one screen. This was only occuring with TwinView, but since i have now more or less solved that, im not too worried about the GDM login screen spanning 2 screens.

I do have a slightly different, although somewhat related issues though. Im using Fluxbox as my WM, and even though I have turned off Full Maximisation, when I maximise a screen, it spans all 3. This is also the case with Mplayer, except that it blanks out 2 of the screens and shows the video on one. On Gnome it works fine, doesnt blank the screens out, but does on Fluxbox.

I should probably repost this in the WM forum as well.

Thanks for the assist. :)