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

am5 motherboard with at least 4 x16 pcie slots for can you put pcie 4x in 16x slot Should you need, or for various reasons decide to mount your graphics card in the second or third PCI-e slot on your motherboard and these only run at 8x or can you put 2 speaker wires in one slot I switched my 3070 to x16 slot today, i didnt know that the second pcie slot was only x4

candy glyph slot Have you also tried to put your video card in second long PCIe slot? Does the card show as x8 when you do that? If yes