You might have already fixed this by now but... Yeah you can use the bottom pci-e slot - you have manually set the jumpers in between them so that they'll operate @ x8/x8 (normally the top slot is @ x16 and the bottom is @ x1). You shouldn't see too much of a slow down (if any) by 'only' using x8 bandwith. I'm doing this on one of my machines atm (due to hsf space issues) and haven't noticed any difference in performance. Hope this helps!