http://i.ebayimg.com/t/PCI-E-PCI-Express-Cable-1X-16X-Riser-Card-2U-1U-/00/$(KGrHqMOKnIE3bd!Rwj7BN9kZ(kuNw~~_35.JPG

Using 2 of these on my open 1x slots, and my 2x 16x slots, means I can have up to 4 GPU's on this machine?