As far as I know, there is a small jumper that usually comes with the card that hooks up between the card and a spot on the motherboard. My old 280 OC and 295 GTX both came with this cable. If you didn't get one try talking to the manufacturer's rep as I couldn't find one unless I tried ebay. When I conacted my rep he sent one free of charge. Gotta love XFX. Also with HDMI you don't need anything else, it carries both digital audio and video.
