Thanks. I had a standard EVGA GtX 670 that I returned because it was very loud. I liked the ASUS DC2 cards because they are much more quiet than the stock cards and a little more quiet than the gigabyte windforce OC. Because there have been problems with the 670 DC2 cards, I was going to go with the 680 rather than the 670. I wonder, do you think the increase in case fan noise that might result from cooling 2 of the ASUS cards in sli would overshadow the relative silence of the ASUS Top?
My case is a Corsair 500r, so I do have a side intake fan.
in the end, the chances of me adding a second card aren't very great, especially if I go with the 680 Top over the 670, but I did want the option just in case.