Qual a diferença en pcie e pcie gen2 ?

PCI Express Gen2 and Gen3, IO Virtualization, FCoE, SSD and PCI Express Storage Devices are here What are PCI Express Storage Devices

There's a setting to choose pci-e version as in gen1, gen2 or gen3; but I don't see a setting to change speed unfortunately

pcie 20 x1 slot The IO configuration of the UP Element i12 EDGE is tailored 3052 PCIe B-key x 1 2280 SATAPCIe x2 M-key x 1

pcie2 slot Gen2 on this mb somehow lane distributionbandwidth layout of mb caused GPU in slot