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

Do I have 3rd gen or 4th gen PCIe slots? pcie gen 4 in gen 3 slot PCI Express Gen 3 x8 but i get the same behaviour if i put it in slot 4 (PCI Express Gen 3 x16 ) is this a known issue pcie expansion slot PCIe Gen 4 offers a massive upgrade over the traditional PCIe Gen 3 SSD The new standard almost doubled the transfer speeds as compared to

pcie 4 in pcie 3 slot ssd PCIe: This interface taps into four of your computer's PCIe lanes to blow away SATA speeds, to the tune of nearly 4GBps over PCIe gen 3