Quote Originally Posted by donmarkoni View Post
If I were you, I would try many combinations to find out. First try PCI-E #1 and #3 and compare findings with these you have now.
This is not the answer you were looking for, but it could be helpful.
Anyway, look down to my reply to kpablo and what I'm going to do, so we'll know if #2 and #4 run @16x if #1 and #3 are not populated.

I doubt that, but not sure. I'll try putting my GTX 480 from slot 1 to slot 2 and post result.
Thanks for the reply, but it was hell setting this up inside and I can't just pop them out and test in slots 1 and 3.

I'm hoping someone that understands the screenshots can tell me from that.

If you could test yours in slot 2 and tell us it would be good.
Like I said. When I called up Asus Tech Support the guy told me I could put
a single card in any PCI-E slot and get 16x. That's what he said, but he could be mistaken too.
When I disabled all my slots except for #2 I got exactly the same results as my screenshots above but for one card.

(If all four slots are not in fact 16x then this board is wrongly advertised as
having FOUR 16x PCI-E slots.)