I just got a Titan X and I am trying to set up a dual monitor display. The titan has 1 DVI, 1 HDMI and 3 DVI-D displays but none of the DVI-D or HDMI work, only the DVI. I tested it on both screens and both worth through DVI. My second (smaller and older) monitor only has VGA and HDMI, so I use a VGA > DVI adapter and it works like charm. Is there anything I have to do to get DVI-D and/or HDMI to work for my dual monitors?