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

What is PCI Express? Do PCIe lanes, slots, and versions matter? pcie slot size Item 4 is the PCIe slot 4, on Riser 2 and is connected to Processor 2, it supports a full height, full length 16x card The slot width is 16x Item 5 is the pcie 50 x16 slot That “x16” is a specification referring to either the x16 PCIe slot form factor or a full x16 lanes of PCI Express bandwidth (

pcie 50 x16 slot PCIe slots come in different sizes, with the most common being PCIe x1, PCIe x4, PCIe x8, and PCIe x16, which indicate the number of lanes

pcieslot Pad, NVME or AHCI SSD to PCIE Adapter Card for Key M 2230, 2242, 2260, 2280 Size SSD, Support PCIe x4 x8 x16 Slot : : Computers & Looks like most recent ATX motherboards have a dramatically reduced number of PCIe slots