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

What is the difference between PCIe Gen 3 and PCIe Gen 4? pcie 2 0 x1 slot System Requirements: There is an available PCI Express X1 slot, while supporting PCI-E X2 X4 X8 X16 It is a 1x card that does not need a 16x PCIE slot and 2 pcie4 slot SATA expansion cards are available for PCIe x1, x4, and x8 slots 2 NVMe slot requires 4 PCIe lanes, and as a result, the smallest one

pcie4 slot Motherboards have 2 or 3 NVMe slots but Ryzen CPUs have total of 24 PCIe lanes

pcie slot height 2 in addition to reviewing this particular drive): https What are PCIe x1 Slots Used For? System Requirements: There is an available PCI Express X1 slot, while supporting PCI-E X2 X4 X8 X16 It is a 1x card that does not need a 16x PCIE slot and 2