When I had a single monitor setup, without Xinerama, with my current setup of Ubuntu 11.10, ATI 5800 series card, Unity showed transparencies, shadows, etc. (although graphics was reported as 'Standard' in the control/settings panel).

Having switched to a dual monitor setup, dell 24" UltraSharp and a smaller Acer monitor, Unity shows only as 2d, even though I'm not loggin in to that display manager.

WebGL performance is very sluggish, I'm getting the impression that the processor is doing all the work and the card isn't even accessible even though the drivers are installed (from the ubuntu repository, I did not compile custom drivers).

Any tips on how to enable full 3D accelerationn and video card support.

Here is my xorg.conf file:

Section "Monitor"
    Identifier   "0-DFP3"
    Option      "VendorName" "ATI Proprietary Driver"
    Option      "ModelName" "Generic Autodetecting Monitor"
    Option      "DPMS" "true"
    Option      "PreferredMode" "1680x1050"
    Option      "TargetRefresh" "60"
    Option      "Position" "0 0"
    Option      "Rotate" "normal"
    Option      "Disable" "false"
EndSection

Section "Monitor"
    Identifier   "0-DFP4"
    Option      "VendorName" "ATI Proprietary Driver"
    Option      "ModelName" "Generic Autodetecting Monitor"
    Option      "DPMS" "true"
    Option      "PreferredMode" "1920x1200"
    Option      "TargetRefresh" "60"
    Option      "Position" "0 0"
    Option      "Rotate" "normal"
    Option      "Disable" "false"
EndSection

Section "Screen"
    Identifier "Default Screen"
    DefaultDepth    24
    SubSection "Display"
    EndSubSection
EndSection

Section "Screen"
    Identifier "amdcccle-Screen[1]-0"
    Device     "amdcccle-Device[1]-0"
    DefaultDepth     24
    SubSection "Display"
        Viewport   0 0
        Depth     24
    EndSubSection
EndSection

Section "Screen"
    Identifier "amdcccle-Screen[1]-1"
    Device     "amdcccle-Device[1]-1"
    DefaultDepth     24
    SubSection "Display"
        Viewport   0 0
        Depth     24
    EndSubSection
EndSection

Section "Module"
    Load  "glx"
EndSection

Section "ServerLayout"
    Identifier     "amdcccle Layout"
    Screen      0  "amdcccle-Screen[1]-0" 0 0
    Screen         "amdcccle-Screen[1]-1" 1920 0
EndSection

Section "Device"
    Identifier  "amdcccle-Device[1]-0"
    Driver      "fglrx"
    Option      "Monitor-DFP4" "0-DFP4"
    BusID       "PCI:1:0:0"
EndSection

Section "Device"
    Identifier  "amdcccle-Device[1]-1"
    Driver      "fglrx"
    Option      "Monitor-DFP3" "0-DFP3"
    BusID       "PCI:1:0:0"
    Screen      1
EndSection

Section "ServerFlags"
    Option      "Xinerama" "on"
EndSection

More info:

fglrxinfo display: :0 screen: 0 OpenGL vendor string: ATI Technologies Inc. OpenGL renderer string: ATI Radeon HD 5800 Series OpenGL version string: 4.1.11005 Compatibility Profile Context