Found this-
Dual Link:
Dual T.D.M.S. (transition minimized differential signaling) "links". DVI can have up to two TMDS links. Each link has three data channels for RGB information with a maximum bandwidth of 165 MHz, which is equal to 165 million pixels per second. Dual-link connections provide bandwidth for resolutions up to 2048 x 1536p.
Single Link:
Single T.D.M.S. link. Each link has three data channels for RGB information with a maximum bandwidth of 165 MHz, which is equal to 165 million pixels per second. Bandwidth for a single-link connection supports resolutions of over 1920 x 1080 at 60 Hz (HDTV).
Dual link vs Single Link:
Don't believe the "hype" some websites are using about dual link cables being superior to single link cables. A single link cable is 100% as good as a dual link cable for single link equipment which covers about 99.5% of current equipment, including HDTV's, Projectors, Plasma Screens, and High Definition Set top Boxes. A better quality cable is a better quality cable, and single and dual link has nothing to do with quality. On the other hand, if both devices being connected support Dual links, then a dual link cable is the proper cable for the application, and you will have the capability of much greater resolutions and refresh rates. A properly designed Dual link cable should have no negative effects when used with single link equipment.
http://www.ramelectronics.net/html/DVI_cables.html
http://www.mycableshop.com/3rd_Level/Video-Flat.htm
