PCIe vs PCIe

As with previous generations, the standard simply doubles the speed that the PCIe slot runs at It now provides about 2GBs per lane

From a numbers standpoint, it depends on the speed of your gen4 drive; but if your drive is capable of higher transfer speeds than gen3

pcie slot size 4 GPU passthrough Blacklisting drivers; How to know if a Some motherboards can't pass through GPUs on the first PCI slot

pcie 30 x1 slot PCIe x16: This is the largest PCIe slot with 16 data lanes PCIe x16 slots are associated with graphics cards and provide the highest bandwidth available