They will be running
Asrock z77 extreme4
16-32 GB DDR3 1600 mhz ram.
SLI Asus GTX 680 TOP
Hi nadz -They are both Delta made units. The the pro 850 has a lot of good reviews, the gamer 900 I
think is newer as it had one, but I'd go with the 850 pro anyways cuzz of the Gold effeciency
vs bronze on the other.
BTW - the Siverstone strider plus (Silver) is also a good unit. Looks like you have three good choices from which to choose.