Your graphics card setup with a PCIe riser cable blocks access to nearby PCIe ports. You could still use a 16x slot for a PCIe riser, but connecting a 4x WiFi card directly to it isn't feasible.
Your graphics card setup with a PCIe riser cable blocks access to nearby PCIe ports. You could still use a 16x slot for a PCIe riser, but connecting a 4x WiFi card directly to it isn't feasible.