What is PCI Express? Do PCIe lanes, slots, and versions matter?

A physical x16 slot can run at x4 theoretical speeds depending on usage and wiring It's why with multiple graphics card set ups you may see

PCIe slots are available in four sizes — x1, x4, x8, and x16 — based on how many individual PCIe lanes run to and from that slot A PCIe x1 slot

pcie m2 slot 2 is a slot that can interface with SATA , PCI Express

pcie2 slot There are two full PCIe X16 slots The blue is the primary one