PCIe x8 NIC in PCIe x16 slot

pcie x 16 slot   Dan pcie 4 ssd in pcie 3 slot

So in the first scenario, both physical x16 slots only provide 8 lanes, in the second scenario the first x16 slot provides 16 lanes (for full

No that's not possible The physical interface of that wireless card is PCIe x1 and the lenght of A x8 card will work in an x1 slot, but will be limited to x1 speeds A x8 card will also work fine in a x4 slot It will be limited to x4 speeds

franks farm slot A x8 card will work in an x1 slot, but will be limited to x1 speeds A x8 card will also work fine in a x4 slot It will be limited to x4 speeds Also the more expensive NVMe PCIe adapters don't need x16 slots, there are x4 models that will simply share the x4 among all the SSDs That