Eu consegui fazer isso funcionar graças a um colega de trabalho. aqui está o meu arquivo xorg.conf. isso requeria o gnome2 e os drivers nvidia proprietários.
Section "ServerLayout"
Identifier "Layout0"
Screen 0 "Screen0" 0 0
Screen 1 "Screen1" RightOf "Screen0"
Screen 2 "Screen2" RightOf "Screen1"
InputDevice "Keyboard0" "CoreKeyboard"
InputDevice "Mouse0" "CorePointer"
Option "Xinerama" "1"
EndSection
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"
EndSection
Section "Files"
EndSection
Section "Module"
Load "glx"
EndSection
Section "Extensions"
Option "Composite" "Disable"
EndSection
Section "InputDevice"
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section "Monitor"
Identifier "Monitor0"
VendorName "Unknown"
ModelName "HP w2207"
HorizSync 24.0 - 82.0
VertRefresh 48.0 - 76.0
Option "DPMS"
EndSection
Section "Monitor"
Identifier "Monitor1"
VendorName "Unknown"
ModelName "HP w2207"
HorizSync 24.0 - 82.0
VertRefresh 48.0 - 76.0
Option "DPMS"
EndSection
Section "Monitor"
Identifier "Monitor2"
VendorName "Unknown"
ModelName "HP w2207"
HorizSync 24.0 - 82.0
VertRefresh 48.0 - 76.0
Option "DPMS"
EndSection
Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "Quadro NVS 295"
BusID "PCI:2:0:0"
Screen 0
Option "Rotate" "CCW"
EndSection
Section "Device"
Identifier "Device1"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "Quadro NVS 295"
BusID "PCI:2:0:0"
Screen 1
Option "Rotate" "CCW"
EndSection
Section "Device"
Identifier "Device2"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "Quadro NVS 295"
BusID "PCI:3:0:0"
Option "Rotate" "CCW"
Screen 0
EndSection
Section "Screen"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
Option "TwinView" "0"
Option "metamodes" "DFP-0: nvidia-auto-select +0+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Screen1"
Device "Device1"
Monitor "Monitor1"
DefaultDepth 24
Option "TwinView" "0"
Option "metamodes" "DFP-1: nvidia-auto-select +0+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Screen2"
Device "Device2"
Monitor "Monitor2"
DefaultDepth 24
Option "TwinView" "0"
Option "metamodes" "DFP-0: nvidia-auto-select +0+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection