So you are saying that Single 4870 > 280 GTX? kinda confusedit all depends on how much you want to spend 390 is a great price for insane performence its just a litle more then a 4870 and it squashes it. .
Im swapping because the board sucks, and im getting the other motherboard for free so yea.I don't see a reason to swap.. but since you have a X48/p45 CrossfireX would be a better option... but HD 4870X2 or HD 4850X2 isn't worth crossfiring