X1 Carbon gen 9 PCIe Issue Linux

I got a X1 Carbon Gen9 through work with the intentions of using an eGPU. My lspci output with and without the eGPU only ever show a LnkSta and LnkCap of Speed 2.5GT/s. This post shows someone getting the 8GT/s on Windows. dmesg looks clean. Maybe you all know something I can poke at or can explain why I seem to not get the maximum link speed?

  • Device: Lenovo X1 Carbon Gen9
  • OS: Arch
  • Kernel: 5.15.8

I think that’s a power saving feature. On Windows if I launch GPU-Z I see the PCIe connection slow down to PCIe 3.0 x1 because the card is not doing much and the system doesen’t waste power sending the full signal through.
Try and check if the speed changes if you put any tipe of load on the GPU. The gears thingy will work too (can’t recall what’s that called).


Picture of my GPU stats right now as an example.

Maybe that has something to do with it. I found some other post relating to that, but I am unsure. When running Unigine on linux, my graphics card fans go crazy, but when running a game with proton, I can only match roughly half of what I can on Windows, and the GPU never takes full effect.

I have a P51 from Lenovo that runs everything fine on Windows, so I am thinking it’s either the laptop or the Proton layer in Steam that is my bottleneck. I guess I need to benchmark some native linux games or simple always use the other device with Windows for all my gaming. I was really hoping this X1 could be the device to rule them all.

There have been other ThinkPads with bad Thunderbolt ports, but I saw that was a few generations back. Maybe I am affected by a hardware issue. I guess I’ll have to try Windows to see if it is the same there.

That totally sounds like a driver issue of some kind or something to do with Proton.

I don’t think it has to do with the Thunderbolt port because I don’t think your GPU would reliably work.
Windows benchmarks are totally needed to get to the bottom of the issue.

Thanks for the notes. Let’s see what Windows has to say!

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