Arc Pro B70 Downgrade to PCIe Gen4 Recurrent?

[B70er]

The issue reported and resolved here seems to be recurrent for me. I own 4 B70's and each individual board may downgrade to gen4, even after I reset it to gen5, for no obvious reason. The config output posted in that message chain seems to point to ASPM as a factor.  Is anyone else experencing this?

[JedG_Intel]

Hello B70er,

Thank you for posting on Intel Community Forum.

To address the issue properly, please share the information below.

1. Are all 4 B70 cards connected simultaneously, or does this happen even with individual cards?

2. Is there a specific trigger that seems to cause the downgrade?

3. What motherboard are you using with these B70 cards?

4. How long do the cards typically stay at Gen5 before downgrading?

5. How are you currently checking the PCIe speed of your graphics card?

Additionally, to have a better understanding of your system configuration and components please generate a complete copy of the System Support Utility (SSU) report. Please follow instructions here and send the report - How to get the Intel® System Support Utility Logs on Windows*

I look forward to your response.

Best regards

Jed G.

Intel Customer Support Technician

[B70er]

Thank you for your time. I do not have all answers for you, but I will do my best here.

> 1. Are all 4 B70 cards connected simultaneously, or does this happen even with individual cards?

Yes, all B70 cards are simulaneously powered up and connected to pcie lanes, nominally operating at 32GT/s x16 (Gen5).

> 2. Is there a specific trigger that seems to cause the downgrade?

No. If I had to guess, I would say that happens when the system is left idle. But I do not know if that is just a coincidence or what the actual trigger is. Sorry. I'm actually hoping you could answer that question for me.

> 3. What motherboard are you using with these B70 cards?

MZ33-AR1. RAM interleaving correctly configured and operating to the extent I can benchmark. The usual BIOS settings relevant to extension boards are all in place as expected. The fact that all cards do simultaneously operate at the nominal gen5 bandwidths is proof of that.

> 4. How long do the cards typically stay at Gen5 before downgrading?

I got the first card about thtree weeks ago, then proceeded to acquire another three in the period of about a week. So there isn't really a representative period of time to say with certainty so far. I did have it happen already three times as I can recall. To be clear, I set pciedowngrade to false on all boards. One day, when doing a monitoring scan I find one that shows that flag as true. This cycle has happened about three times.

> 5. How are you currently checking the PCIe speed of your graphics card?

I do not suggest anyone to use any individual tool because they all seem to provide stale information, I suppose depending on the particular way the downgrade took place and how soon after that you are checking on it. I go through a range of tools like lspci but I never use any single tool in isolation, I go all the way from the PCI Invenory listing in BMC to the level zero tests like ze_peak before I'm convinced a card is operating at gen4 - or at gen5 for that matter, sorry.

I do not have a windows partition on that server and I will not run the SSU, but I do hope you too can start providing some answers here. Looking forward to having you telling me something about the B70 that I don't already know.

Thanks,

---

[JedG_Intel]

Hi B70er,

Thank you for providing the requested information. I will review the details and conduct further investigation. I will get back to you as soon as I have an update or if any additional information is required.

Best regards,

Jed G.

Intel Customer Support Technician

[JedG_Intel]

Hi B70er,

We are currently investigating the issue regarding the B70 getting PCIe downgraded to PCIe4 and we require additional information on what could trigger the issue.

A possible explanation to the incorrect figures is that unlike AMD and NVIDIA graphics cards, Intel Arc cards report their PCIe link speed differently to the lspci utility. While other manufacturers present their cards as a single device block (PEG device), Arc cards appear as a PCIe chain structure. If you query the incorrect segment of this chain, you'll get a misleading link speed reading of x1 instead of the card's true link speed.

To help us further isolate the issue, please perform the following and share the output to us.

1. Provide a general system view by getting Intel® System Support Utility for the Linux* Operating System
2. install the intel-graphics Personal Package Archive (PPA) for Ubuntu 25.10 and 24.04 or use for Ubu… to make the graphics card work correctly.
3. Follow the steps below to get the actual speed of your Intel Arc Graphics card:
4. Open a terminal
5. Run the command: sudo lspci -tv
6. Based on the output obtain the root of the GPU device chain for example: +-06.0-[01-04]----00.0-[02-04]--+-01.0-[03]----00.0 Intel Corporation DG2 [Arc A380] 
7. The root of the case is 06.0
8. Convert the root in to a tree entry by adding 00: before the root, for example: 00:06.
9. Once the root has been found, run the following command: sudo lspci -vv -s 00:06.0 | grep -E "LnkCap|LnkSta"

Note: Remember to change the root for the value you see after running sudo lspci -tv

If you have any questions, please let me know.

Best regards,

Jed G.

Intel Customer Support Technician

[B70er]

This is just a short update for those experiencing similar issues:

The issue is recurrent. In other words, the flag for "downgrade to gen4" does reset itself to true (when it should not do that), even after being maually reset to false (so the board operated at gen5 bandwidths). Troubleshooting issues related to bandwidth negotiation between boards like this is difficult, and if you then consider all aspects that could influence the issue both on the motherboard and on the gpu, it does get a bit complex. So @JedG_Intel , I'm not going to try to do that here. The best I can do is to provide the serial number of the boards that were returned to Intel through the store displaying the issue so you can try to find them there. I did have two other boards display the same behavior after a period of weeks not showing any symptoms at all, bringing the total to 4 boards affected (out of 4, so all of them). I really don't know what really triggers the behavior, but the fact is that the flag in the gpu firmware does flip. That is not the motherboard negotiating at a lower bandwidth then the gpu can do, it is the gpu itself reset to a downgraded state. And there is zero documentation on that flag that I could find so far.

Thanks, 

[ArchieD_Intel]

Hi B70er,

Thank you for your feedback. I wanted to let you know that I've reviewed this thread and am currently investigating the links you shared along with the symptoms and behavior you cited regarding the GPU. I'm analyzing the information to better understand the scope of the problem and identify potential solutions.

I'll continue my investigation and will follow up with you once I have more findings to share as soon as possible. 

Best regards,

Archie D.

Intel Customer Support Engineer

[B70er]

The only new piece of information for you is this: out of six boards I have had on my system, four have displaied the symptom, two have not and work flawlessly (so far). All the boards that failed had serial numbers ending in 402 (and the box did not have the intel/arc/pro/b70 printed on them). They all worked for about a week (4 to 6 cold boots give or take) before the flag flipped for the first time. The two boards that seem to be stable have serial numbers ending in 404 (and the boxes have intel,etc...  printed on them). There is nothing else I could identify as far as firmware version, benchmark results accross several language models/runtimes, just general response, that distinguishes them. When they work, they all seem equally spec'ed, equally capable, and I cannot distiguish them.

[ArchieD_Intel]

Hi B70er,

Thank you for the feedback that you shared. For me to investigate this further, please share the Power Supply make and model.

Additionally, to gain a comprehensive understanding of your system, please use the System Support Utility (SSU). This tool will generate a text file compiling all your system information. You can follow the instructions at this link and send the text file here. Help Guide for the Intel® System Support Utility.

Best regards,

Archie D.

Intel Customer Support Engineer

[ArchieD_Intel]

Hi B70er,

I just wanted to follow up to see if you had a chance to review the information I posted. Your feedback at your earliest convenience would be greatly appreciated. Thank you. 

Best regards,

Archie D.

Intel Customer Support Engineer

[ArchieD_Intel]

Hi B70er,

Since I haven't received a response from you, I will be closing this inquiry. If you need further assistance, please submit a new question, as this thread will no longer be monitored.

Best regards,

Archie D.

Intel Customer Support Engineer