I'm trying to get two entire different screen to work on my Mac Pro on a HD5870 graphic card, and I need help with this. I'm trying to hook up a 42inch HDTV (max res. 1920 x 1080) via mini-display/HDMI and a 22inch monitor (max res. 1600 x 1200) direct from DVI. I just got two white blank screen. What is the thing I did wrong? Please advice.