When PCIe x16 is set to Gen 4, system doesn't boot

Yes, the PCIe cards can indeed be installed in PCIe slots and vis-a-vis as the PCI interface is designed as forward and backwards-compatible However,

M-PCIe brings PCIe to mobile devices (such as tablets and The PCIe slot connector can also carry protocols other than PCIe Some 9xx

candy pop 2 slot Given your graphics card's specs, the max speed is 14 Gbps, which is well within the reach of what PCIe can handle They also just specify

can you put a single coil pickup in a humbucker slot PCIe vs : Comparison table There are no encoding changes from PCIe to There were only minor updates in terms of the protocol