Can I use a Gen 4 NVMe SSd in a Gen 2 slot?

Can I use a Gen 4 NVMe SSd in a Gen 2 slot? pcie nvme slot 2 drives are “keyed” at one end so as to prevent the end-user from inserting them in an incompatible socket PCIe NVMe drives are 'M' keyed SATA ones, pcie 1 slot 2 slot You can see two standard slots on the PCB, between the PCIe slots These have the mounting holes for horizontally mounting

pcie 1 slot The NVMe drives don't fit in the slot You have to use a PCIe adapter Consequently you are limited by the number of PCI slots, but I'm not

pcie x4 in x16 slot If you're looking to add a PCI ExpressNVMe drive to a desktop with an older motherboard that lacks slots, one option is an drive on a carrier card  2 drives are “keyed” at one end so as to prevent the end-user from inserting them in an incompatible socket PCIe NVMe drives are 'M' keyed SATA ones,