‎NVMe SSD slot Generation compatibility?

Two types of PCIe slot on an Asus H81M-K motherboard Various slots on a computer motherboard, from top to bottom: PCI Express x4; PCI Express x16; PCI Express

PCIe Gen 3 vs PCIe Gen 4 PCIe offers twice the data rate and maximum bandwidth of PCIe , allowing faster data transfers The standard

william hill slot tournaments This arrangement enables NVMe to offer almost four times the IO and ten times the seek time NVMe drives are so much faster than SATA drives

william hill slot games Looking at Amazon there is PCIe Gen 3 NVME and PCIe Gen 4 NVME for sale I don't see this even mentioned on the Wikipedia page for NVM Express