You know, I thought it was just bad luck when the last motherboard I got from ASUS wouldn't fit into either of the two mid-tower cases I tried it in. But now I know it is due to poor design work by ASUS. I am now at the point I will never buy another board from them.
This one has the nice problem that the third PCI-E slot, the only one on the second bus, which means it is the one you should use for a second graphics card for maximum performance, just does NOT allow a double height graphics card to fit in it.
If you try, you find that the card is too low on the board and a) overhangs the bottom of the board, which means it can be blocked by the PSU, or by the bottom of the case, depending on how your case is layed out, and b) it cannot be pushed into the slot anyway due to the fact it is blocked by a board component itself, the HD-Audio external socket and the USB external sockets.
This could have EASILLY been fixed by moving the PCI-E third slot up by one, and putting the 1xPCI-E (the little mini PCI-E slot) at the bottom, where there are NEVER double height PCI-E devices, where double height 16xPCI-E like graphics cards, are common as dirt.
All in all, I am tired of ASUS just not bothering to think through the layout of their boards. I'm done with them.