*All pcs, except those with that new chip thing (it was mentioned this morning by Gorman) that allows you to pair up all sorts of cards. I think its just that the technology doesnt allow the interaction yet.
It's because of the way that SLi & Crossfire works, if you have two cards that perform differently then it will cause tearing and artifacts as one half of the screen is rendered faster than the other. (in theory) lol
