PCIe x8 NIC in PCIe x16 slot

How will a PCIe Gen x 4 SSD perform in a PCIe slot? pcie 3 0 x4 slot to recognize a fake My Computer•98K views · 9:31 · Go to channel · Will PCIe x1 x4 cards pcie slot length tl;dr: Has anyone tried an Apple OEM SSUBX SSD in the PCIe x16 Slot 2 of a Mac Pro 3,1 ? Does it negotiate PCIe

pcie x 16 slot 2 NVMe Switch Adapter is a high-performance data transfer solution that allows users to connect up to four NVMe drives to their PCIe x16 slot