When I boot up my computer and it gets to the logon screen, the display actually spreads across the two of them like I would expect. Once I login it reverts to each monitor cloning the other and the desktop is no longer stretched across both of them. Once I get going I can go into the Nvidia settings and set the displays to stretch again but the settings aren't persistent.
Here's my /etc/X11/xorg.conf
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 331.20 (buildd@roseapple) Mon Feb 3 15:07:22 UTC 2014
Section "ServerLayout"
Identifier "Layout0"
Screen 0 "Screen0" 0 0
InputDevice "Keyboard0" "CoreKeyboard"
InputDevice "Mouse0" "CorePointer"
Option "Xinerama" "0"
EndSection
Section "Files"
EndSection
Section "InputDevice"
# generated from default
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"
EndSection
Section "InputDevice"
# generated from default
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section "Monitor"
# HorizSync source: edid, VertRefresh source: edid
Identifier "Monitor0"
VendorName "Unknown"
ModelName "HYO DUAL-DVI"
HorizSync 88.8 - 88.8
VertRefresh 60.0
Option "DPMS"
EndSection
Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce GTX 650 Ti"
EndSection
Section "Screen"
# Removed Option "metamodes" "DVI-I-1: 2560x1440_60 +2560+0, DVI-D-0: 2560x1440_60 +0+0"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
Option "Stereo" "0"
Option "nvidiaXineramaInfoOrder" "DFP-0"
Option "metamodes" "DVI-I-1: nvidia-auto-select +2560+0, DVI-D-0: 2560x1440_60 +0+0"
Option "SLI" "Off"
Option "MultiGPU" "Off"
Option "BaseMosaic" "off"
SubSection "Display"
Depth 24
EndSubSection
EndSection
How do I get the settings to persist through logging in?
It looks like this question might be a dupe of this one but that one was closed as too localized for reasons that I can't figure out.