Originally Posted by iARDAs
Thanks for the explanation mate
I was thinking of grabbing myself an all PCI 3.0 16 mobo but there is no need it seems
I will also SLI but perhaps if the temperatures are not good enough, I MIGHT get a motherboard with 3 PCI slots so I can leave a gap for the top GPU to breathe a bit better.
In your case I wouldn't worry about heat too much either. You've got a card that exhausts the hot air outside the case (a 'blower type' design). These cards generally run a bit hotter themselves compared to open designs as seen on many non-reference cards, but when running SLI you won't have the cards heating up each other. My card (the Asus GTX670 DCUII) has one of these open designs and exhausts a lot of hot air into the case itself. When running SLI, I think this might lead to the cards heating up each other a little bit. But we'll see
Also, with the Sabertooth Z77, you've got an empty slot in between the cards (as long as you leave it empty of course). I think that will be enough to provide your cards with enough fresh air. There are boards with even more space in between (mostly the extreme boards with 4 PCIe slots, like the Maximus V Extreme or Gigabyte GA-Z77X-UP7), but then you'd need a special size SLI bridge, you'd have waste possibly a lot
of money on a board with features you really do not need, and your second card will be closer to the PSU (or the metal plate in your 800D, which might also prevent fresh air from reaching it, although your 800D is probably so big that this won't be an issue at all). In general, I think the kind of spacing between slots on the Sabertooth Z77 is about as good as it gets (and it's pretty standard nowadays).
(btw, the Sabertooth Z77 does have an extra PCIe 2.0 x4 slot, but I wouldn't recommend using it as PCIe 2.0 x4 is actually a more significant bit slower, and it might be harder to get fresh air over there as well).
I'd say enjoy your awesome SLI setup