PCIe 3.0 x4 NVMe SSD only runs at PCIe 3.0 x1 in an x4 capable M.2 slot

[halbleiter]

I recently bought a used Z2 Mini G3 Workstation and added an HP Z Turbo Drive G2 SSD (Samsung) to the on-board M.2 slot. To my big surprise, the SSD runs at quarter speed compared to when the same SSD is installed in an HP Z440 Workstation (with help of an HP PCIe Adapter). There is a simple explanation: The SSD runs only on a single lane in my Z2 Mini G3 Workstation. However, HP claims in various documents (data sheet, quickspecs, technical white paper) that the M.2 2280 slot is PCIe Gen3 x4. In another attempt, I tried an Intel 760p SSD which also only runs at x1. I checked the BIOS settings but there is nothing to do except the ability to hide the M.2 slot from the OS. Does HP artificially limit the number of PCIe lanes which are accessible by a NVMe SSD installed in the M.2 slot? I can't believe that this the case for a pretty expensive Mini Workstation which is advertised as "CAD Workstation".

Any idea or hints about this? Thanks a lot in advance!

[Daniel2908]

I had the same problem on an extensive desktop pc (x2 instead of x4). After searching the net i found out (and you can read a lot of this here in the forum, too) that HP limits it indeed in most of their systems. And because they limit the bIOS too and dont give the user more rights, i think you will have to life with that if their is no solution again. I wish you that there is a solution for your workstation. 

[halbleiter]

Thanks, I know, I have seen similar responses from other users of this forum. There might be technical reasons to limit the number of lanes on an M.2 NVMe slot, for instance driven by power supply or cooling constraints, but I expect in this case that this is mentioned somewhere in the spec sheet of the product. And I would not have spent the money for a rather expensive (compared to other vendors) HP Z Turbo Drive G2 SSD including proper heatsink if I would have known in advance that it only runs on a single lane in that particular M.2 slot.