Section "Device"
        Identifier      "Configured Video Device"

        # Add this line to force the driver
        Driver          "intel"
EndSection

Section "Screen"
        Identifier      "Default Screen"
        Monitor         "Configured Monitor"

        #Enable external monitor to have larger resolution that boot-time screen
        SubSection "Display"
                Virtual         1920 1200

                # OR, if you want to have a 1920x1200 monitor and the 1280x800 built-in
                #     screen (1920+1280 = 3200) :
                #Virtual         3200 1200
        EndSubSection
EndSection