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

[halbleiter]

Hello community, I just bought a used Z2 Mini G3 Workstation and added a HP Z Turbo Drive G2 SSD (Samsung) to the M.2 slot on the motherboard. However, the SSD runs only at a fraction of the expected speed, about a quarter of what the same SSD is able to accomplish in a HP Z440 Workstation, using a HP PCie x4 adapter. Samsung Magician software reports PCIe 3.0 x4 in the Z440 and only PCie 3.0 x1 in the Z2 Mini G3. However, the Z2 Mini G3 data sheet claims PCIe 3.0 x4 for the M.2 2280 slot on the motherboard. Why it is only running at x1? I checked the BIOS but there is nothing to do, except an option to disable the M.2 slot to hide it from the OS. What needs to be done to let the SSD run at x4? It seems that all 4 lanes are physically connected to the M.2 slot but for unknown reason the SSD connects only to a single lane. Is this enforced by HP to save power in the Mini Workstation? Thanks a lot in advance!

[DGroves]

is this a entry or performance model? it does matter as they are different

which M.2 socket are you using? one is x4 the other is x1  see link below

https://www8.hp.com/h20195/v2/GetDocument.aspx?docname=c05262508

[halbleiter]

Thanks for your reply. It's an entry model. As far as I can see in the official HP product spec sheet, performance and entry differ in regard to graphics (and power supply, 135W vs. 200W), but not in regard to the capabilities of the M.2 2280 slot.

https://support.hp.com/za-en/document/c05338666#AbT11

Expansion slots

(1) 30 mm (1.18 in) M.2 slot (PCIe Gen3 x1)

note: For WLAN/BT M.2 module only

(1) 80 mm (3.15 in) M.2 slot (PCIe Gen3 x4)

And yes, there are two M.2 slots on the motherboard but only one of them takes 80mm cards (the x4 slot). The x1 slot is limited to 30mm cards where my 80mm SSD would not fit. Furthermore, the x1 slot has B-keying while the x4 slot has M-keying. Since the Samsung SSD has M-keying it won't fit into the x1 slot M.2 connector. Thanks for your help!

[DGroves]

some systems will either drop ssd lanes, or disable the ssd slot depending on how the bios options are configured

my system will (limit ssd lanes from 4 to 2) and disable a pci-e slot or SATA ports depending on what options i use/configure in the bios

i recommend you read the user manual to see if this is a possibility

[halbleiter]

Thanks, the user manual doesn't provide any help because it simply claims PCIe Gen3 x4 for that slot. I have tried many things including disabling SATA port or the M.2 WLAN/BT x1 slot. The M.2. 2280 NVMe remains on single lane. I tried to call HP and the immediate reaction of the support guy to my "complaint" was that "this is an entry model". My reference to the data sheet that there is no difference made between entry and performance model in regard to M.2 NVMe slot capabilities didn't help. He offered to check it and let me wait on the phone for 20 min before the call got automatically terminated.