Originally Posted by johnv
I just was thinking, that you should make sure that your two cards are not setup for SLI. SLI will supposedly not work for what you are trying to accomplish.
Also, once you have made sure that nvidia and not nouveau is the only video driver:
in /etc/modprobe.d/fbdev-blacklist, add:
~# sudo update-initramfs
~# sudo update-grub #or what update what bootmanager you use
to make sure modules aren't loaded from the initramfs.
Then you can reboot into single user mode to have a fresh environment (this will be as root); run:
~# Xorg -configure
~# nvidia-xconfig -f ./xorg.conf.new -o ./xorg.conf
Things went OK until the Xorg - configure.
There were some error messages (6 things that weren't working IIRC).
Nvidia-xconfig would not run.
Now I have a single screen at a 1280 x 800 resolution. see next response.