My new Mac Pro with Snow Leopard is having problems with screen resolution. With my old Power Mac G5 (10.5.8) I used 1680 X 1050 with no problems. If I connect the new Mac Pro to this monitor (ACER AL2251W) i get a floating box that says 'Input not supported'. So I have to change the resolution to something that is not to my liking.

Has anyone experienced this problem?