Just installed this card in slot 1 in my MP5,1. It's brand new one. I made sure the firmware switch on the card was to the right for the Mac OS X. Both power cables that came with the card were employed. I connected a 23" ACD via DVI to MDP and attach to the left most MDP (furthest away from the HDMI port). When I Startup the screen lights up and at about the time the login panel is about to display the screen goes black. If I disconnect the ACD from the MDP when the screen has gone black and then reconnect it to the same port the screen lights up and the login display appears. If I connect to the other MDP the issue does not arise. If I connect directly to the DVI the issue does not arise. Any clues why the screen should go black as I've described ? Thanks.