PCIe x4, x8, x16 Drive Adapters and Converters

pcie 3 0 x4 slot   Dan pcie slot for gpu

slot 2,3,4,5,6 and 7 respectively DMI2

If three slots are in use, the third is x4 From the Asrock specs page  Supports PCIe motherboards and is backward compatible with PCIe and PCIe ; also supports PCIe x4 bus slot and is compatible with x8 x16 bus slot

prada188 slot 2 slots — supporting both PCIe and — that allow you to expand your system with high-performance SSD storage Designed for the latest generation of NVMe Note, the 9207's are PCI-E x4 cards The issue you are going to have is that desktop CPUs have a limit amount of PCI-E lanes to go around