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

Maybe upgrading is pointless… - PCI-E Gen 4 vs Gen 3 pcie gen 4 in gen 3 slot ATX with 12th13th Generation Intel® Core™ LGA1700 Socket Processors, TDP Max PCIe Gen 3 x 1 pcie slot width However, PCIe Gen 4 increases the bandwidth to approximately 8GBs, allowing the system to utilize the full potential of the NVMe drive As

pcie slot for gpu Slot configurations without DWCM​ ; Slot 36, PCIe x8, Empty ; Figure 4 Rear view with 4 PCIe slots ; Riser 1, x16x8x8 , x16x16E ; Slot 1