sli is 2 video cards to share the load of just one, its suppose to give you better performance in sli supported games (doom 3, far cry, riddick) but in some of the benchmarks ive seen, 1 card can do better. its your choice, but id wait till later this summer to see what ati has in store for its next gen cards. (similar to the one that they put in xbox 2) still overall thats a great system, your making me jealous now.