If there were any problems with Crossfire or SLI compatible GPUS fitting on their respective boards, they would have surely have that all sorted out by now. If you have 2 -2 slot cards in SLI or Crossfire, there is not much room between them, that is true, but it is enough if you have good case airflow.
if the gfx card wasn't a two slot card (which it is)....but pretty much all respectable gfx cards are these days.
I understand it's two slots . . . Like i said ; there is a pciex16 slot, underneath that a small slot ( don't know how it's called ) and than the second pcie slot, so imo there is room left. ( not much but enough i think ) The first gpu takes the space of the pcie slot and the small one and the second gpu in the second pcie slot pointing downwards.
I currently have a similar setup (different MB, but the same spacing) with two 6970's.
If the PCI slots on the MB have only one PCI slot between them then the two cards will basically be *touching*. Since AMD cards take air in from the side, the #1 card (closest to the CPU) will be struggling for fresh air and, when running under load, the fan will ramp up to very high speed. It's loud as hell and really annoying.
The card you got has an over-sized fan than the "standard" AMD 69xx video cards, so it may not be as much of an issue.
Can the #1 card get enough air to stay cool enough to run and do the cards still work? Yes. Is the air the #1 card gets pre-warmed by the back of the #2 card? Obviously. Does the #1 card run at +90C and have it's fan near 100% when doing any heavy gaming? Yes.
The side-intake design is pretty poor, IMO. You might think they would have "sorted it all out by now", but obviously they've sorted it by saying "just run the fan really high" and not by coming up with a really good design, or recommending you always shop for a MB with 2 non-video card (i.e. "non 16x") slots between the video card slots.
...note about the MB in the pic; the Dark Blue and the WHITE slots are for the video cards - so you have two slots between them, the light-blue slots go unused.
Note that I have seen some cards with ports in the back and / or sloped back covers to allow air to get in from the back of the card when they're butted together in a crossfire / SLI setup.
Note that Kosak is correct - you can put some folded cardboard or something between the cards at the top - bending them slightly in their slots - to give the #1 card better access to air flow. I tried this last night and it helped quite a bit. Even just opening the gap up by a millimeter or two is worth it. I got that new MB set up today, and the airflow is no longer an issue for me...