For many months I’ve had a 3rd monitor on my desk, but could not use it as I could not get it to work. Any time I enabled the monitor using Xinerama, the desktop would freeze on login.
I’ve now learned about how the whole XOrg and Nvidia Settings system works.
The trick is that many of the display settings for the nvidia driver are no longer relevant to Xorg.conf, and are now actually in a file in your home directory called .nvidia-settings-rc.
If you are having problems try wiping this file out, and also wipe out your /etc/X11/xorg.conf
Then, if you have SLI cards, issue sudo nvidia-config –sli=on
If you have a single card but MultiGPU, issue sudo nvidia-config –multigpu=on
If you have a SLI MultiGPU card (4+ GPU) then you only need sli, as Xorg.conf told me that multigpu was not necessary at that point.
I’m using the latest Ubuntu 14.04 nvidia-331-updates-uvm driver, which is running more stable than the nvidia-343-uvm from xorg-edgers ppa, so I do not recommend updating to 343.
Once you reboot, run the nvidia settings and ensure Base Mosaic is enabled, and enable all of your monitors in the order you want, and click the Save to X Config button.
But one detail I did not know that caused me so many issues in the past – that all of the OTHER nvidia settings has to be saved separately to that nvidia-settings-rc file.
This file should be saved automatically on close of the settings app, but to be sure go to the nvidia-settings Configuration panel and hit the save button, and simply select your home folder that it opens up to.
Now one important note, when you hit the Save to X button, its going to wipe out your SLI/MultiGPU option! So you need to go back and re-run sudo nvidia-config –sli=on or –multigpu=on to reset that setting.
Now you should be good to restart and have your working setup! I was able to get over 400 FPS in Minecraft (which given its simplicity of graphics, it is a Java game and not the best for performance).
I now have 2 more monitors on the way for Wednesday so I can be close to that “Geek Dream” of a 6+ monitor setup (I’ll be at 5 for now), but hoping to not have any issues with them.
Good luck 🙂2