Buy Pi+® PCI-E x1 to NVMe SSD Expansion Card

Yes, a x1 card should work in a x16 slot It's good that you've got it to work in a x1 slot What else have you tried it in besides the x16 slot

You can install PCI Express slots in larger slots but not smaller ones For example, you can install a PCI Express x1 adapter into an x16 slot (but will still

pcie m2 slot NICs work well in x1 slots, especially the single-port 1G or dual-port 1G Quad-port 1G won't be able to fully saturate all 4 ports at the

pcie slot height NVMe PCIe® x4 & PCIe® x2 • 1x PCIe ® Slot 2 2280 • NVMe PCIe x4 and SATA Mode 12 Smart Fan 5 + FAN STOP • 3 Fan