I recently bought a used PCIE Optane 900p (480GB) but when I install it, it only gets a PCIE 3.0 x2 connection instead of the expected x4.
I have tried installing it in both my motherboard’s primary x16 slot (lanes go directly to CPU) and in the secondary x16 slot (only supports max PCIE 3.0 x4 electrically, lanes go through chipset), and both times I get the same result of x2 negotiated link. My GPU gets full x16 lanes when in the primary slot and x4 lanes when in secondary, so the problem seems to be specific to the Optane SSD. I’ve also tried reseating the card several times and cleaning the contacts with isopropyl alcohol, to no effect.
My system:
Motherboard: MSI MAG B550M Mortar WiFi
CPU: Ryzen 5800X
RAM: 32GB DDR4 3600MHz
GPU (currently in x16 slot): RTX 2070 Super
SSD (currently in primary x4 M.2 slot): Samsung 970 Evo Plus
Optane SSD (currently in secondary x16 slot)
As it stands, the drive is capped to a maximum of 2 GB/s throughput (in practice I’m seeing a max of 1637.744 MB/s sequential 1MiB (Q8, T1) reads in CrystalDiskMark), until this issue can be fixed.
Any ideas of what could be the cause or possible solutions?
Unfortunately, my motherboard BIOS doesn’t have an option to manually set the slot width for the secondary x16 slot. There is an option for the primary x16 slot where my GPU is, but that setting is for PCIe bifurcation cards, which I am not using.
Have you inspected the pcb of the card? Any cracks, weird things going on? I remember some stories of systems shipped with heavy graphics cards running in 8x instead of 16x due to cracks in the PCB destroying some lanes. This was shipping damage due to the weight of the cards.
Do you have some other PC to test with? BIOS up to date?
There is some wear on the PCIe contacts, but nothing that appears catastrophic. See photos. The rest of the PCB is behind the heatsink and I’d rather not take it apart.
No other PC to test with, unfortunately. I think I’m one or two BIOS versions behind the latest, but I don’t think it is the cause. I’ll try updating it tonight just in case.
