xorg.conf changes from nvidia-setting have no effect after reboot

I recently installed 14.04, and found the exact same problem. I tried setting left and right screens in nvidia-settings manager but when I rebooted or restarted X they would switch back.

Searched a lot online, but couldn't find a solution, then I just went to the Displays options in Ubuntu System Settings or unity-control-center, set everything there, and voila, problem solved.

So the easiest thing to do is ignore nvidia-settings and use the displays option in the Ubuntu settings. At least in Ubuntu 14.04.

I had the same problem in Ubuntu 14.04. It turned out that xorg.conf was overridden by unity-control-center displays settings which are stored in ~/.config/monitors.xml.

Entering the desired settings into monitors.xml solved the issue for me.

• <primary>no</primary> or <primary>yes</primary>
• <x>0</x> means left screen, <x>1280</x> right screen where 1280 is width of the screen on the left.

I had a similar issue - not multi-monitor, but my settings were getting ignored like yours are. What I did to solve it was replace the nvidia-auto-select option with the actual resolution I wanted, i.e. 1280x1024_75 +0+0.

So you might try something like this:

Option         "metamodes" "CRT-0: 1680x1050_75 +1680+0, DFP-1: 1680x1050_75 +0+0"

Additionally, I noticed that in the above line, the monitors are in the order "CRT-0, DFP-1", whereas earlier in your config file they're ordered "DFP-1, CRT-0". I don't know if that matters, but these flip-flops may also be causing your issue, so try setting everything in the same order.

What I think was happening for me was that the nvidia x-server would load its preferred settings, then would be overridden by the settings manager. By removing the auto-select (and any other resolution options available in /etc/X11/xorg.conf) I think it disallows the use of other resolution settings.