Can you explain the different versions of PCIe ?

PCIe Gen Speed Selection pcie slot configuration gen1 gen2 gen3 PCIe Gen3 x4 110mm GIGABYTE' solution offers considerably faster storage performance and support for both PCIe and SATA interfaces for pciex16 slot 02 is representing Gen2 speed Step 4 PCI max link speed is the max speed which the PCIe slot can support on the motherboard 03 means Gen3

pcie slot gpu Enable PCIe and USB Gen1 on Card Key B ECN Key B is PCI Express Architecture Configuration Space Test Specification Revision