Want to know the second slot is PCIe Gen 4 or

Pcie Lanes Connectx-3 NIC question pcie 3 slot The adapter card I am looking at can be used in a X4, X8 or X16 PCIe slot and they say I will get up to 32Gbps when it is plugged into a PCIe pcie 50 slot PCIe bifurcation PCI Express bifurcated Riser Card ITX to ATX x4x4x4x4

pcie gen 4 in gen 3 slot But what about the fallback to PCIe , for example runs an older AMD or current Nvidia graphics card in such a slot? In order to remain really