Hi everyone, I’m looking for some help diagnosing a weird PCIe link issue.

1) Problem summary

• On my ASUS TUF B550M system, my Intel Arc A380 negotiates as PCIe x1 (max appears to be x1).

• What’s confusing is that when I check the device at 01:00.0, it sometimes looks like the capability is x16/x8 (so it looks normal on paper), but when I check it elsewhere (ex: 03:00.0) the actual link reports x1.

• I’ve seen people mention “Arc sometimes shows x1 but isn’t actually limited,” but in my case hardware transcoding is unstable (sometimes works, sometimes fails with errors), so I don’t think it’s just cosmetic.

• I also tried a dummy HDMI plug (no change).

2) Software / versions

• Unraid: 7.2.2

• Jellyfin: 10.11.5 (Docker)

• FFmpeg: 7.1.3

• Jellyfin with Hardware Acceleration: None → plays fine (but CPU usage is high).

• With HW accel enabled → transcoding is intermittent / errors occur.

3) Hardware specs

• Motherboard: ASUS TUF B550M (BIOS: latest)

• CPU: Ryzen PRO 5750G (APU)

  • Also tested with Ryzen 7 5700X (same issue)

• RAM: SK hynix ECC 32GB ×2 (64GB total)

• GPU: Intel Arc A380 (75W, slot-powered)

• PSU: SuperFlower 850W Platinum

• HBA/RAID card: LSI 9207-8i (IT mode) (tested removed as well)

4) Cross-tests (important)

• The Arc A380 works perfectly on other motherboards:

  • On an X670E board: works great (x8)

  • On a B850 board: works great (x8)

• On my current ASUS TUF B550M, other GPUs work fine:

  • GT 710 works

  • RTX 5060 LP works

  • I swapped cards back and forth to confirm.

So it really seems like a compatibility/handshake issue between A380 and this specific B550M setup, not a dead GPU or a completely broken PCIe slot.

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5) Everything I’ve tried (full list)

Reseating / physical checks

• Reseated the GPU multiple times (power + seating checked)

• Suspected it wasn’t fully seated due to case alignment → removed/disassembled I/O area and reseated carefully

• Cleaned GPU gold fingers with an eraser

• Tried dummy HDMI plug

CPU / socket pressure tests

• Loosened CPU cooler pressure / adjusted mounting tension

• Reseated the CPU

• Swapped CPU (5750G ↔ 5700X) to test

BIOS / settings

• Tested ASPM ON and OFF (both)

• BIOS reset / defaults loaded

• CSM OFF

• Resizable BAR ON

• Above 4G Decoding ON

• Forced PCIe speed:

  • Auto

  • Gen3 locked

  • (no change)

PCIe configuration simplification (lane sharing / conflicts)

• Removed the LSI 9207-8i HBA and tested GPU as the only PCIe card

• Removed all NVMe drives

• Still negotiates x1

Boot / kernel parameters (Unraid)

• Disabled boot options like “Wait for F1 if error”

• Tried booting with:

  • append initrd=/bzroot i915.enable_guc=2 pcie_aspm=off pci=realloc

Power suspicion

• Considered PSU/power limits, but A380 is 75W and PSU is 850W Platinum, so I’m treating power as unlikely.

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6) Questions / what I need help with

1. Are there known cases of Arc A380 negotiating x1 only on certain B550 boards (BIOS/AGESA/PCIe training/compatibility)?

2. Any idea why 01:00.0 shows normal capability, but another address like 03:00.0 reports the link as x1? What does that usually imply?

3. Are there any specific BIOS options I should check beyond what I already tried (AER, PCIe native power management, SR-IOV, ACS, etc.)?

4. What’s the best way to prove whether it’s “display-only x1” vs a real x1 limitation? (Which logs/commands are most reliable?)

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7) Info I can provide immediately if needed

• Full lspci -vv output (especially the 01:00.0 and 03:00.0 sections)

• lspci -tv

Thanks in advance—any pointers or “check this one specific thing” suggestions would be really appreciated.

Edited January 2Jan 2 by Programbins

Try your attachments again. Doesn't look like you allowed them to complete.

30 minutes ago, trurl said:

Try your attachments again. Doesn't look like you allowed them to complete.

I copy-pasted an image, but it left some artifacts. I edited the post to clean it up

https://www.intel.com/content/www/us/en/support/articles/000094587/graphics.html its´s a bug