Is a MacPro3,1 x16 slot PCIe or ?

Non-hot-plug PCI riser board slot definitions pcie2 slot Primary riser cage connector, connected to processor 1 or the southbridge PCIe 3-slot riser cage* PCIe 2-slot x16 riser cage 1 patrick slot I own Asrock 990 FX Extreme 3 and I'm sure I put graphic card in X16 slot,it's in PCIE2 slot But why is it running in X4 mode,and how to

rainforest magic bingo slot Be sure nothing is shorting the contacts to the PCIE2 slot underneath the mother board As said above, be sure the video card is fully seated in