I go to www.hardocp.com almost everyday to get some advices. They always said to get SLI setup etc...etc..I didn't, didn't have the 1000$ (CAN) but I had the 800$. This means no new PC for a couple of years now. In [h] forum, they buy new cards every week or so.
Ho btw, my x800xt-pe is an asus brand, when my fan died, they gave me a completly new card, new box, so new bundle with new webcam (got 2 now). The only bad point is that it took about one month and a half.
And from what I see here, the X700XT wins vs 6600gt.
