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Comment by MayeulC | Hacker News Reader

IIRC AMD doesn't validate the ECC functionality on their ryzen chips? So you could theoretically end up with a defective ECC circuitry if unlucky. I think that was the case for the first generations, it may also have changed or I may be misremembering.

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> IIRC AMD doesn't validate the ECC functionality on their ryzen chips? So you could theoretically end up with a defective ECC circuitry if unlucky.

This is not the case.

Ryzen, Threadripper, and EPYC use a unified memory controller that has fully validated/qualified/supported ECC capability. The only difference between the memory controllers in these CPUs is the number of them (Threadripper and EPYC will have multiple memory controller to support the extra memory channels).

When AMD claims that ECC on Ryzen isn't validated, they're talking about the platform as a whole, not the CPU specifically. ECC support on consumer CPUs depends on the motherboard supporting it. Unlike on Threadripper and EPYC (and also unlike Intel's approach), ECC is not a guaranteed feature of the Ryzen platform, so people who want that functionality need to explicitly looks for motherboards that have it (in the same way that you'd need to explicitly verify PCIe bifurcation support).

However, if the motherboard supports it, ECC on Ryzen is a fully supported, validated, you-can-RMA-if-it-doesn't-work feature.

That was in the past (true for Zen 1 and Zen 2 Ryzen). It is no longer true (after Intel enabled ECC in some desktop SKUs, starting with Alder Lake, AMD plussed by validating ECC in all desktop and mobile Ryzens).

Now all Zen 3 and Zen 4 CPUs, both desktop and laptop, have explicit ECC support, which means that ECC must be validated by AMD in all of them.

If any current AMD CPU happened to have defective ECC, that would be a completely defective CPU, which must be replaced by the vendor.

Despite the fact that all laptop Ryzen 6000 and Ryzen 7000 CPUs support ECC, I have not seen yet any AMD laptop or SFF computer with ECC support. On the other hand it is much easier to find AM5 MBs with ECC support than Intel W680 MBs.

The AMD website says the non-PRO 7x40 laptop Ryzens have no ECC support[1], and the Framework folks have said that AMD told them there’s no ECC on non-PRO 7x40 laptop Ryzens[2]. If plugged in, ECC modules will work, but without the error-correction functions.

(Edited to reflect the current state of the website, as it used to say ECC support was present[3].)

[1] e.g. https://www.amd.com/en/product/13186

[2] https://community.frame.work/t/responded-amd-batch-1-guild/2...

[3] https://web.archive.org/web/20230513075641/https://www.amd.c... (here “FP7r2” is the version for use with interchangeable DDR5 modules rather than with soldered LPDDR5)

This is very weird.

I have saved the page from your link on the 17th of July. In the saved page it is written:

"ECC Support: Yes (FP7r2 only; Requires platform support)"

The same was written at all AMD Rembrandt and Phoenix models, and it has been written in all such mobile CPU specifications at least since the beginning of 2022, so at least during a year and a half, if not more.

The ECC support was available only with DDR5 SODIMM memory, not with LPDDR5 memory, and only in the FP7r2 package, and neither in the FP7 nor in the FP8 packages.

Perhaps AMD has discontinued the FP7r2 package, but this is not mentioned in the specifications. Either that, or they have decided right now that they may charge more for PRO models, or save on testing on non-PRO models.

Either way, it seems a stupid move for AMD to degrade right now their mobile CPU specifications, when Intel will launch Meteor Lake, which is likely to be better than AMD Phoenix. AMD mobile Zen 5 will be better than Meteor Lake, but until its launch it remains about a half of year, supposing that it will not be delayed.

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