Section "Monitor"
  Identifier "DVI1"
  Option "ignore" "true"
EndSection

Section "Monitor"
  Identifier "DVI2"
  Option "ignore" "true"
EndSection

Section "Device"
  Identifier "X4500MHD"
  Driver "intel"
  Option "monitor-DVI1" "DVI1"
  Option "monitor-DVI2" "DVI2"
EndSection