The difference between PCIe x1, x4, x8, x16 and x32

An expansion slot refers to any of the slots on a motherboard PCIe x16, two PCIe x1, and two PCI expansion slots

PCIe links that use fewer lanes to use the same interface as PCIe links that use more lanes For example, a PCIe x8 card could plug into a PCIe x16 slot

pciex1_1 slot 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

pcie 30 in 40 slot PCIe x16 Gen5 expansion backplane; 5x PCIe x16 Gen slots; 1x PCIe x16 Gen target slot; Optional bifurcation to support two PCIe x16