Well, that depends on what SC you're looking at I guess. I have a 560Ti SC that has dual fans. http://www.newegg.com/Product/Product.a ... 6814130651
$100, craigslist. Just took one creepy meeting (to me...long story), but it folds 24/7 and cool as a cucumber.
The Vanilla $265 (at the time) single fan Asus 560Ti that's clocked down a bit? Just as cool doing the same work. And clocks and fan adjustments can usually be made up using RivaTuner in a decent user's hands. It's a cool card either way is all I'm saying. I don't see a BIT of difference in the multi-fan, gold plated, double barrel, get-ups. Even the ones that look like they port it directly out the back, don't. There's enough leaks in the shroud to negate any positive direction and how I feel these open designs get away with not worrying too much about it.
It just needs a nudge rearward and it'll get there. Heat doesn't radiate from moving air as easily as it looks...it's not water in a pipe and shouldn't be thought about it like that. The motto here is to shop wisely, pick a good brand, and get the least expensive one.