I have a Power Mac G4 (AGP Graphics) and recently got a working 15" Studio Display with an ADC connector. I had to install an ADC video card for the Mac as well. The Mac turns on fine, but it doesn't give power to the display. Also when I plug in a VGA monitor into the same video card it doesn't detect it either, which makes me think I need a driver for it, but doesn't OS X install drivers automatically? Am I doing something wrong? Does the AGP Graphics Power Mac even support ADC video cards, or do I need a DVI > ADC converter?