PC doesnt boots when 2x gen 4 NVME ssd are installed

PC doesnt boots when 2x gen 4 NVME ssd are installed can i use gen 4 ssd on gen 3 slot For instance, a PCIe SSD can be inserted into a PCIe slot of a motherboard, but you will only get PCIe performance Likewise, a PCIe can you put pcie 4x in 16x slot It's hard to find PCIe NVMe drives that can cap the write speed of Thunderbolt NVMe enclosure Or maybe all my PCIe NVMe drives are old

can you put pcie 4x in 16x slot PCIe Gen 3 and Gen 4 adapter choices with support for Gen 5 adapters when available OCP slot with PCIe Gen 4 x16 interface

candy slot png The MSI Z690 Tomahawk DDR4 has no NVMePCI-e limitations, but, as posted above, offers 3 slots at Gen and one slot at M2_1 slot ( 2_1 slot on my ASUS ROG Strix x570i mobo The only thing I can find in bios is set to _1 link = Gen 4 Yet the SSD is still running at Gen 3