What is the difference between PCIe Gen 3 and PCIe Gen 4?

Max speed of PCIE for SSD m 2 pcie 4 0 in 3 0 slot As with previous generations, the standard simply doubles the speed that the PCIe slot runs at It now provides about 2GBs per lane m2 nvme slot Biostar ; 1, 1 x AMD Socket AM4 CPU ; 2, 4 x DIMM DDR4-4933+ ; 3, 4 x SATA III Connectors ; 4, 1 x PCIe x4 Slots ; 5, 1 x PCIe x4 Slots

m2 slot A PCIe SSD would not be any slower in a PCIe slot because its maximum speed is that of PCIe PCIe SSDs cannot go any faster than PCIe