I'm trying to get my two Radeon HD 4770 cards working with three monitors. Xinerama works so far in the way that I have two fully working monitors were I can move windows from one to the other.

My problem now is that my third monitor is a clone of my second monitor (displaying the exact same thing). These monitors are connected to the same graphic card ("Screen Middle" and "Screen Right" in the xorg.conf below).

Here is my xorg.conf:

Section "ServerLayout"
    Identifier   "ThreeMonitors"
    Screen       "Screen Left" 0 0
    Screen       "Screen Middle" RightOf "Screen Left"
    Screen       "Screen Right" RightOf "Screen Middle"
    Option       "Xinerama"
EndSection

Section "Monitor"
    Identifier  "Monitor Left"
    Option      "DPMS"
EndSection

Section "Monitor"
    Identifier  "Monitor Middle"
    Option      "DPMS"
EndSection

Section "Monitor"
    Identifier  "Monitor Right"
    Option      "DPMS"
EndSection

Section "Device"
    Identifier  "Device Left"
    Driver      "radeon"
    VendorName  "ATI Technologies Inc"
    BoardName   "ATI Radeon HD 4770 [RV740]"
    BusID       "PCI:3:0:0"
    Screen        0
EndSection

Section "Screen"
    Identifier "Screen Left"
    Device     "Device Left"
    Monitor    "Monitor Left"
    SubSection "Display"
           Depth    24
    EndSubSection
EndSection

Section "Device"
    Identifier  "Device Middle"
    Driver      "radeon"
    VendorName  "ATI Technologies Inc"
    BoardName   "ATI Radeon HD 4770 [RV740]"
    BusID       "PCI:2:0:0"
    Screen        0
EndSection

Section "Screen"
    Identifier "Screen Middle"
    Device     "Device Middle"
    Monitor    "Monitor Middle"
    SubSection "Display"
           Depth    24
    EndSubSection
EndSection

Section "Device"
    Identifier  "Device Right"
    Driver      "radeon"
    VendorName  "ATI Technologies Inc"
    BoardName   "ATI Radeon HD 4770 [RV740]"
    BusID       "PCI:2:0:1"
    Screen        1
EndSection

Section "Screen"
    Identifier "Screen Right"
    Device     "Device Right"
    Monitor    "Monitor Right"
    SubSection "Display"
           Depth    24
    EndSubSection
EndSection

I'm using a fresh Kubuntu 10.10 installation with propsed-updates enabled since this repo contains a xorg fix for using multiple graphic cards.

I hope someone can help me out. Very many thanks!!