[citation][nom]motamedn[/nom]Forgive me if i'm wrong, but couldn't he be talking about the fortress? I've heard mixed things about the efficiency of air cooling in that case with 2xCF.[/citation]The Fortress 2 has good airflow, but any time you crowd cards together you're asking for a heat problem. My friend is having the same problem with 3x GTX 285 in his Cosmos-S.
So, the Fortress 2 fits cards up to the 5970...but you have to remove the fan grill for the 5970. Anything even slightly shorter fits without removing the fan grill. It can hold up to three double-slot cards, depending on the motherboard you use. If the last video card slot is the second slot from the bottom, the card fits.
If you try to put a double-slot card into the bottom slot of a motherboard, you'll run into problems as the card overtakes drive area. That's not a problem with the Silverstone case, it's a problem with a bad motherboard design.
Loads of companies make poorly designed motherboards with the third card in the bottom slot...examples are all of Gigabyte's X58 and most Asus X58 boards. The only X58 boards with the slots laid out properly from Asus are the P6T, some of the WS-series, and the Rampage III Extreme.