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,

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