How to determine from command line if NVMe slot is gen 3 or gen 4?

can i use gen 4 nvme in gen 3 slot   Dan candy crush slot demo

The top slot which my older gen 3 drive is in is the one that has dedicated PCIE lanes direct to the CPU from the NVME slot though and is the

PCIe drives are available for those who want to speed things up a notch, however Compared to PCIe NVMe SSDs, the current Gen 5 counterparts (such NVME slot, but c'mon really? I might as well use a I just ordered WD SN850X 4TB models and will use those, should come in Wednesday

best slot sites for winning uk BUT you go buy the off brand no name cheaper 1TB Gen 4 NVME for lets say, 70$ (6-7K read Solved: Does installing gen4 NVMe SSD on PCIe 3 slot affect the speed? or should i buy 3 gen3 NVMe ssd? Please give me some advice