video card upgrades for this mobo. cpu ram and ssd/hdd are all obvious and easy choices. the difficulty I found was in video cards. I want to take advantage of the 4 slots my board offers but the newer xpensive cards seem to occupy slot width( x 2) I.e. I could at most use 2 cards. and if that is necessary I spose the best I could get is the gtx 690 . can u confirm this is the most economical upgrade from my twin radeon hd5670's?