I’m using the latest and greatest xubuntu.  I had a very difficult time getting X.org setup to recognize my dual monitor setup.

Here is the link that was my solution.  I had to download a custom EDID configuration file.  I had this fixed months ago and forgot what the solution was.  Then this week, the problem came back.  One of my monitors was stuck at 640×480.  I do all the suggested updates on a weekly basis.  I also shutdown my workstation every night.  Seems that one of the recent updates caused my GPU to recognize my monitors in a different order.

Below is my xorg.conf file.  Notice the CustomEDID changed from DFP-1 to DFP-0.

Section “Monitor”
Identifier     “Monitor0″
VendorName     “ViewSonic”
ModelName      “ViewSonic VX2025wm”
HorizSync       30.0 – 82.0
VertRefresh     50.0 – 75.0
Option         “DPMS”
EndSection

Section “Screen”
Identifier     “Screen0″
Device         “Device0″
Monitor        “Monitor0″
Option         “NvAGP” “2″
Option         “NoLogo” “1″
Option         “RenderAccel” “1″
Option         “CursorShadow” “1″
Option         “Coolbits” “1″
Option         “ConnectedMonitor” “dfp, dfp”
Option         “NoPowerConnectorCheck”
Option         “UseEdidFreqs” “False”
Option         “TwinView” “True”
Option         “MetaModes” “nvidia-auto-select, nvidia-auto-select”
#    Option “CustomEDID” “DFP-1:/home/user/X11/edid.bin”
Option “CustomEDID” “DFP-0:/home/user/X11/edid.bin”
DefaultDepth    24
SubSection “Display”
Viewport    0 0
Depth       24
Modes      “1680×1050″
EndSubSection
EndSection

Section “Module”
Load    ”glx”
Disable    ”dri2″
EndSection

Section “ServerLayout”
Identifier     “Default Layout”
Screen      0  “Screen0″ 0 0
Option         “Xinerama” “0″
EndSection

Section “Device”
Identifier     “Device0″
VendorName     “NVIDIA Corporation”
BoardName      “GeForce 9500 GT”
Option         “TwinView” “True”
Driver           “nvidia”
EndSection