Motherboard pci express x16 slot specification details explained in

pcie slot x16   Dan pcie 20 x1 slot

when you inserted the card in the top pcie 16 slot did it click in place? also what does the gpu info page in the bios say page 130 of the

By you sticking a UAD-2 card into the second slot, the motherboard detects this and automatically throttles the first slot down to 8x assuming you have stuck in Physically yes, the slot connector for an x4 is generally smaller and PCIe is designed that smaller cards can occupy larger slots if needed

juno 168 slot PCIe x16 is your 16-lane PCI Express slot, or at least your largestlongest PCI Express slot It is the most high-bandwidth, high-performance expansion slot The Matrox C900 PCIe x16 graphic card powers nine displays from a single board to easily build 3x3 video walls P690 Plus LP PCI Matrox P690 Plus LP PCI -