Using PCIe 2.0 x1 Slots - CPUs, Motherboards, and Memory - Linus Tech Tips
Put Graphics card with PCI Express 2.0 into PCI Express x1 slot - Super User
Are there any PCIe 2.0 (x1) expansion cards available to add USB-C to a desktop PC? Both of my x16 slots are taken up by my GPU; I have four PCIe 2.0 (