What are the Differences between Gen4 and Gen3 PCIe SSDs?

2 slots will support both M Readwrite speeds of the top NVMe SSDs on the market can exceed 3000 MBs , with some Gen 4 NVMe PCIe

Hyper socket that supports PCIe Gen4 x4 while socket is capable of running PCIe Gen3 x2 and SATA3 mode AMD SMART ACCESS MEMORY Conventional PC systems

m2 slot screw 2 but its for futureproofing, In the near future I'll most definitely have a system with gen 4 and the price difference between the gen 3 and

m2 nvme slot 2 drives on older PCIe motherboards which didn't have native slots, and still saw significant improvement over the early 120GB SATA SSDs