Isolatedevice not working correctly with fglrx

For troubleshooting purposes on two videocards I use isolatedevice on one of my primary video card. And nothing else to my aticonfig --initial
Note I have two cards in machine, but I want it to pretend like theres only one. So I would of thought that when u use IsolateDevice that it would prevent the os from looking for another card. But when i use it not only does it seek out the card still, but fails loading it correctly. Any ideas?

Code:

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Section "ServerLayout"
        Identifier    "aticonfig Layout"
        Screen      0  "aticonfig-Screen[0]-0" 0 0
        Option "IsolateDevice" "PCI:1:0:0"
        Option        "AutoAddDevices" "off"
        # This option disables VGA and VBE calls on IRQ 10, to avoid
        # calls for a card interfering with the others.  See also the
        # file "xorg.conf.probe".
#        Option          "NoInt10"      "Yes"
 
EndSection

Section "Device"
        Identifier  "aticonfig-Device[0]-0"
        Driver      "fglrx"
        BusID      "PCI:1:0:0"
        ChipID      0x95C5
EndSection

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