I bought a Power Mac G5 2.0GHz dual processor (M9032LL/A, A1047) off craigslist for $60. I also have an A1081 20" Apple display. The video card on the G5 has 2 ports: an ADC at port 1 and a dvi-i on port 2. The monitor has a dvi connector. When I connect the monitor on the dvi (port 2) and power the computer on, nothing displays on the monitor. I've never used either of these devices before, but the computer boots into target mode when connected by firewire to my macbook pro and I can take screenshots and view them in target mode. I do not know if a monitor needs to be connected to the adc on port 1 for a SECOND monitor to work at port 2, but I only have the one monitor that connects to port 2.