The bandwidth that a single link has means that the maximum resolution for a single link DVI connection is 1900x1200. So for larger resolutions (link a 30") you need a dual link connection. Note that this does not mean that there are twice as many pins, two cables or that one link carries the top half of the screen and the other the bottom. There are two TDMS transceivers at both ends and they send at the same time, but out of sequence so as they don't interfere. So the top of the screen gets sent by both links at the same time resulting in twice the bandwidth