The 2-into-1 cable is for HD TVs or HD monitors. Only, the card really can't support this anyways (there was a bit of a fuss about this I think). No video card today can really support HD, because they've all be using loose definitions of what that means. Anyways, don't bother. It's for getting the signal out to a very high quality monitor/TV. Just use the normal one for your monitor.
