I have a X8DTU-F main board and using a PCI-e x16 video card on the RSC-R2UU-E8E16 riser card, but my card is only using pci-e x8 bandwidth. What is the issue?
The pci-e x16 slot (SXB1) on the motherboard is by default set to run as two x8 slots. In order to make it run as a single x16 slot please change the foll setting in the BIOS: Under Advanced go to Advanced Chipset Control and change the “Slot SXB1 Width” to x16.