Question PSA: AMD X670E PCIe 5.0 M2 slots slowdown issue, being investigated

igor_kavinski · Oct 4, 2024

Crucial Discovers Flaw in AMD X670E Motherboards: Gen 5 NVMe Slots Drop to Gen 1 Speeds, Cause Boot Issues

Memory and SSD maker Crucial noticed an uptick in support requests by users claiming that their Gen 5 or Gen 4 NVMe SSDs would drop to PCIe Gen 1 speeds, besides being unable to boot into Windows after a restart. Crucial then did some digging, and localized the issue to users with motherboards...

www.techpowerup.com

Not good. Hope they figure out the root cause and push out a remedial patch/BIOS soon.

Hail The Brain Slug · Oct 4, 2024

igor_kavinski said:
Crucial Discovers Flaw in AMD X670E Motherboards: Gen 5 NVMe Slots Drop to Gen 1 Speeds, Cause Boot Issues

Memory and SSD maker Crucial noticed an uptick in support requests by users claiming that their Gen 5 or Gen 4 NVMe SSDs would drop to PCIe Gen 1 speeds, besides being unable to boot into Windows after a restart. Crucial then did some digging, and localized the issue to users with motherboards...

www.techpowerup.com

Not good. Hope they figure out the root cause and push out a remedial patch/BIOS soon.

Considering this is the first I've ever heard of this issue, and it appears to only occur with this one, specific SSD, I am skeptical it's entirely the motherboard's fault.

Otherwise we would have had enthusiasts who have bought into gen 5 drives since release day complaining, as they can only be reasonably used at gen 5 speeds on AM5 anyway.

The actual root cause will be interesting to learn. But I think blaming AMD's platform when only this one drive has the issue is a little premature.

Hail The Brain Slug · Oct 4, 2024

Also considering AM5 is the official PCI-e 5.0 validation platform, why did Crucial not find this before releasing the drive during their own in-house validation?

Dave3000 · Oct 4, 2024

I have a Samsung 2TB 980 Pro NVMe SSD connected to the 1st M.2 slot, which is the only M.2 slot of my motherboard that uses the CPU lanes, of my MSI X670E Tomahawk motherboard. If I install my drive into any of the other M.2 slots of my motherboard, CrystalDiskMark's random 4k write test will drop to around 147 MB/s. When this drive is installed into the 1st M.2 slot (CPU lanes) it gets around 227 MB/s for CrystalDiskMark's random 4k write. Is this related in any way of what is being described in that article? Does the issue in that article listed in this thread happen to every brand of NVMe drives as well when used with a motherboard with an X670E chipset?

Hail The Brain Slug · Oct 4, 2024

Dave3000 said:
I have a Samsung 2TB 980 Pro NVMe SSD connected to the 1st M.2 slot, which is the only M.2 slot of my motherboard that uses the CPU lanes, of my MSI X670E Tomahawk motherboard. If I install my drive into any of the other M.2 slots of my motherboard, CrystalDiskMark's random 4k write test will drop to around 147 MB/s. When this drive is installed into the 1st M.2 slot (CPU lanes) it gets around 227 MB/s for CrystalDiskMark's random 4k write. Is this related in any way of what is being described in that article? Does the issue in that article listed in this thread happen to every brand of NVMe drives as well when used with a motherboard with an X670E chipset?

This is because there is overhead while using the chipset-derived lanes. It's normal.

It's why I won't buy a board without two CPU M.2 slots. I am very upset most of the new 800 series board designs are taking x4 lanes from the CPU for USB 4. Use chipset lanes for that crap!

igor_kavinski · Oct 5, 2024

Hail The Brain Slug said:
I am very upset most of the new 800 series board designs are taking x4 lanes from the CPU for USB 4. Use chipset lanes for that crap!

Probably a strategy to force people to buy more expensive mobos that do things right or move to Shimada Peak when it eventually gets released.

AdamK47 · Oct 14, 2024

Is the problem a Crucial / X670E problem or an all PCIE 5.0 m.2 SSD issue?

Can't say I've experienced it. At least not felt it.

AdamK47 · Oct 14, 2024

igor_kavinski said:
Probably a strategy to force people to buy more expensive mobos that do things right or move to Shimada Peak when it eventually gets released.

Hardware unboxed went as far to say X870E and X670E are the same, just rebranded.

gdansk · Oct 14, 2024

AdamK47 said:
Hardware unboxed went as far to say X870E and X670E are the same, just rebranded.

Yes, it's the same chipset (2 x Promontory 21) in both.

DAPUNISHER · Oct 14, 2024

I played the survivorship bias card over the AM4 fTPM stuttering issues because I'd used so many AM4 systems and never experienced it. Turned out to be a PITA for many owners. The lesson learned, was to take these kinds of reports seriously and not try to wave them off as nothing burgers or blame other companies.

DaaQ · Oct 15, 2024

AdamK47 said:
Hardware unboxed went as far to say X870E and X670E are the same, just rebranded.

gdansk said:
Yes, it's the same chipset (2 x Promontory 21) in both.

It is looking like the X870 non e, would be the B650? IDK the names of the lower chipsets. But the X870 is one Promontory 21.
Please correct if wrong.

Steltek · Oct 15, 2024

DaaQ said:
It is looking like the X870 non e, would be the B650? IDK the names of the lower chipsets. But the X870 is one Promontory 21.
Please correct if wrong.

AMD X870 Flagship Roundup: Zen 5 Motherboards Are Here

AMD's new 800-series chipsets are officially here, but are they worth the upgrade? We'll dive into performance, features, and pricing of the X870E motherboards from Asus, Asrock,...

www.techspot.com

Feature comparison:

CP5670 · Oct 16, 2024

Dave3000 said:
I have a Samsung 2TB 980 Pro NVMe SSD connected to the 1st M.2 slot, which is the only M.2 slot of my motherboard that uses the CPU lanes, of my MSI X670E Tomahawk motherboard. If I install my drive into any of the other M.2 slots of my motherboard, CrystalDiskMark's random 4k write test will drop to around 147 MB/s. When this drive is installed into the 1st M.2 slot (CPU lanes) it gets around 227 MB/s for CrystalDiskMark's random 4k write. Is this related in any way of what is being described in that article? Does the issue in that article listed in this thread happen to every brand of NVMe drives as well when used with a motherboard with an X670E chipset?

I have the same board and only saw a speed drop on the last M.2 slot with a PCIE card installed, which is to be expected as they share bandwidth. If I keep that PCIE slot empty, there is no speed drop on any slot.

Also it's interesting how X670E and X870E are nearly identical. There are X670E boards with USB 4.0 if you really need that. It feels like this chipset exists just to allow motherboard makers to sell more boards.

AdamK47 · Oct 16, 2024

CP5670 said:
I have the same board and only saw a speed drop on the last M.2 slot with a PCIE card installed, which is to be expected as they share bandwidth. If I keep that PCIE slot empty, there is no speed drop on any slot.

Also it's interesting how X670E and X870E are nearly identical. There are X670E boards with USB 4.0 if you really need that. It feels like this chipset exists just to allow motherboard makers to sell more boards.

My Asus ROG X670E Crosshair Extreme has USB4/Thunderbolt thanks to an Intel controller.

The bad thing about it is that it shares bandwidth with the primary m.2 slot. Probably why AMD dedicates lanes to it on the X870E. I keep the USB 4 controller turned off in the BIOS. Don't need it.

lopri · Oct 16, 2024

Do you get back the x4 lanes if you turn off USB4 in the BIOS?

Lane sharing is inevitable because there just are not enough lanes to go around. Out of total 28, 4 go to the chipset and 4 go to USB4. That leaves just 20 for GPU and one M.2. I do not mind x8 for GPU but fundamentally Intel and AMD need to provide more lanes.

And there is this:

https://www.amd.com/en/products/processors/desktops/ryzen/9000-series/amd-ryzen-9-9950x.html

I do not know where x4 Gen4 lanes have gone.

AdamK47 · Oct 16, 2024

lopri said:
Do you get back the x4 lanes if you turn off USB4 in the BIOS?

Lane sharing is inevitable because there just are not enough lanes to go around. Out of total 28, 4 go to the chipset and 4 go to USB4. That leaves just 20 for GPU and one M.2. I do not mind x8 for GPU but fundamentally Intel and AMD need to provide more lanes.

And there is this:

View attachment 109555

https://www.amd.com/en/products/processors/desktops/ryzen/9000-series/amd-ryzen-9-9950x.html

I do not know where x4 Gen4 lanes have gone.

You get the lane bandwidth back dedicated to the 1st m.2 slot.

Edit - The lane sharing was mentioned in this Hero review:

ASUS ROG Crosshair X670E HERO Review

ASUS presents the ROG Crosshair X670E HERO. Featuring a top of the line 18+2+2 VRM using 110 A power stages, USB4 ports, PCIe Gen 5 slots and four M.2 sockets all packed into the standard ATX form factor. Follow along as we take a deep dive and check out all the features this motherboard has to...

www.techpowerup.com

DaaQ · Oct 17, 2024

So someone is sourcing VRM waterblocks.

Question PSA: AMD X670E PCIe 5.0 M2 slots slowdown issue, being investigated

igor_kavinski

Lifer

Crucial Discovers Flaw in AMD X670E Motherboards: Gen 5 NVMe Slots Drop to Gen 1 Speeds, Cause Boot Issues

Hail The Brain Slug

Diamond Member

Crucial Discovers Flaw in AMD X670E Motherboards: Gen 5 NVMe Slots Drop to Gen 1 Speeds, Cause Boot Issues

Hail The Brain Slug

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Dave3000

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Hail The Brain Slug

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igor_kavinski

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AdamK47

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AdamK47

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gdansk

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DAPUNISHER

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DaaQ

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Steltek

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AMD X870 Flagship Roundup: Zen 5 Motherboards Are Here

CP5670

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AdamK47

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lopri

Elite Member

AdamK47

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ASUS ROG Crosshair X670E HERO Review

DaaQ

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