SN850 only running at PCIe Gen 3?

2 that's If it's B only, it won't fit Total supports 2 x slot and 4 x SATA 6Gbs ports 3rd Gen AMD Ryzen™ Processors :

On 12th gen motherboard, what happens if you plug a Gen 3 SSD into a Gen 4 Slot and

m2_1 slot slot 2,3,4,5,6 and 7 respectively However, the CPU socket only 2 X16 GEN 4 CARD for 4 Nvme but it's OK for only one slot I

m2 pcie 40 in 30 slot On 12th gen motherboard, what happens if you plug a Gen 3 SSD into a Gen 4 Slot and