then just get extenders and connect all your cards to x1 ports and one at the x16.
in a personal comment I wouldn't be investing on boards or video cards GPU. You will never get your investment back. I recommend investing on ASIC.
http://www.ebay.com/itm/Gigabyte-Technology-GA-890FXA-UD5-Socket-AM3-Motherboard-/281143778240?pt=Motherboards&hash=item4175799bc0
http://www.ebay.com/itm/MSI-890FXA-GD70-Socket-AM3-AMD-Support-USB-3-0-SATA-6Gb-s-Motherboard-FREE-SHIP-/141024688264?pt=Motherboards&hash=item20d5b9f888
Those are for AMD's.
yeah i already have 1 asic
i.m doing this for litecoins. good thing for gpus is that they can be sold for other than mining purposes.