Does any PCIe slot support NVMe SSD's automatically or do I need

Gen4 NVMe SSD On Gen3 Motherboard? Will It Run can i use gen 4 ssd on gen 3 slot But ya You will be limited to speeds until you put it in a matching slot If devices didn't work in slots there would be a LOT can you use ddr5 in ddr4 slot This drive installs into an available 2280 PCIe x4 slot Advanced features such as dynamic write acceleration, error correction code , TRIM support

can i use gen 4 nvme in gen 3 slot SSD is backward compatible with PCIe Using a Gen 3 PCIe motherboard will enable the user to reach speeds of up to 3400 MBs and 3000 MBs