What is the difference between PCIe Gen 3 and PCIe Gen 4?

Does PCIe matter? PCIe vs GAMING! does the pcie slot matter for gpu If you do this on a B550 or X570 board you'll be limited to PCIe x8 bandwidth when using the RTX 3080 and that limits you to PCIe x16 does it matter which pcie slot i use PCIe NVMe SSD

does it matter what pcie slot i use PCIe slots are universally compatible regardless of version as long as the graphics card fits PCIe lane count is crucial