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

SYONCON PCIe Multiplier, PCIe Splitter 1 to 4 PCI-Express 16X Slots Riser Card, PCI-E 1X to External 4 USB Adapter for BTC Miner Machine GPU Mining ·

Slot 2, PCI Express x16 ; Slot 3, Slot not available on this board ; Slot 4, Slot not available on this board ; Slot 5, PCI Express x8 in a

pcie 4 m2 in pcie 3 slot 4-3, per single PCI Segment Group show less , ECN, November 18, 2018 Errata for the PCI Express® Base Specification Revision , , Errata, October 31

pcie gen 4 in gen 3 slot It should be backward compatible, but you will see less performance than if you had it in a PCIe slot since it runs at PCIe x8 instead