Not many Graphics cards can max out a 8x slot, So if your getting on of the new 5800 series or GTX300 series that can Max out the 8x slot, so there will be suffering...
Right now I'm in a wallet dilemma can't decide to go for duel 16x with a 1366 Board and 920 or 1156 with only 1 16x and 860...
In a nut shell the 1366 set up is going to cost me 250$ more... making my total computer cost... well too much...