What exactly does the spec “PCIe x16 slot ” mean?

The physical size of a PCIe slot can vary depending on the number of lanes it has A x16 slot is typically around 164mm in length and around

Common slot configurations include x1, x4, x8, and x16, which represent the number of data lanes available for communication

pcie cem slot I explain in this video what devices PCIe x1 slots are used for on a motherboard I also attempt

pcie training error slot 1 Card capacity and size Mac Pro has eight PCIe x16* sized slots that accept many different types of PCIe cards: Slot 8 is x4 in size Mac Pro Expansion