I have a Power Macintosh 7200/120 with a PC Compatibility card and an IMS Twin Turbo Video card installed. If I am using built-in video, the PC Setup control panel allows for configuration of my 20-inch display. If I am using the IMS video card, the PC Setup control panel only allows configuration of a 640 x 480 display. What could be causing this?
When a PC Compatibility card is present, the correct video driver to use with the IMS Twin Turbo video card is version 3.6. Older versions of the driver may not provide full functionality for the display you are using.