I'm running 2 nvidia gtx680 in sli mode along w/ a 22", 24", and 20" monitors and driver 325.15
Go in the termininal and write this or copy and paste these lines
"sudo nvidia-xconfig --base-mosaic"
Then go into the nvidia gui interface and then setup your monitors position.
If you have 2 video cards, then run this command ""sudo nvidia-xconfig --sli=Mosaic" or --sli=On (I didn't notice a difference between the 2)
restart desktop and your done!!!
I hope this helps for anyone else who was having the issue I was having.
xorg.conf file
# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig: version 325.15 (buildmeister@swio-display-x64-rhel04-03) Wed Jul 31 19:04:27 PDT 2013
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 325.15 (buildd@lakoocha) Thu Aug 8 11:32:52 UTC 2013
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"
Identifier "Monitor0"
VendorName "Unknown"
ModelName "Acer V226HQL"
HorizSync 31.0 - 83.0
VertRefresh 56.0 - 76.0
Option "DPMS"
EndSection
Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce GTX 680"
EndSection
Section "Screen"
# Removed Option "SLI" "On"
# Removed Option "BaseMosaic" "True"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
Option "Stereo" "0"
Option "nvidiaXineramaInfoOrder" "DFP-3"
Option "metamodes" "GPU-a857a4ce-fc6a-4b2b-9b58-25904611b1a5.GPU-0.DVI-I-1: nvidia-auto-select +0+0, GPU-a857a4ce-fc6a-4b2b-9b58-25904611b1a5.GPU-0.DVI-D-0: nvidia-auto-select +1920+0, GPU-82ad0620-1db9-e25c-1d39-91950fa73a0a.GPU-1.DVI-I-1: nvidia-auto-select +3840+0"
Option "MultiGPU" "Off"
Option "BaseMosaic" "on"
Option "SLI" "On"
SubSection "Display"
Depth 24
EndSubSection
EndSection