AMD Ryzen 9 7900X Performance With ECC DDR5 Memory

[piorunz]

One of the fun thing of using consumer boards that support ECC is that you can overclock the RAM and, due to the aforementioned error-correcting functionality, it makes it not just way easier to find stability but also gives you that extra peace of mind that, even if some random teeny bit of instability managed to slip through, it'll get corrected on-the-fly anyway.

Yes, that is a great feature. I did that with my workstation PC. Because DDR4 ECC 3600 MT/s did not exist at the time, and 3600 is apparently a sweet-spot speed for my CPU, I bought two 32GB 3200 MT/s sticks. Selected 3600 speed in BIOS, rebooted... And it has been working like that ever since. Timings the same (conservative ECC ones), stability rock solid, tested with various programs, including memtest. Not one ECC error report yet. Computer is a AMD Ryzen 7 5800X in ASUS PRIME B550-PLUS.
Fun fact that I had two internal cache ECC corrections within CPU. Linux is reporting these events. But not on DDR4 memory yet.

[piorunz]

This is the most ignorant thing I've read in a while. What's scary is how confidently you proclaim it.

No, you just misunderstood my post. And if my simple post shocks you, you haven't been reading any internet lately it seems.

So, why the higher latency spec? That's only because they used conservative timing and adhere strictly to JEDEC specifications. They also tend not to have heatspreaders on them, like you often to see on "gaming" DIMMs. So, I'm not sure how much the specs are down to reducing heat dissipation or power consumption.

That's exactly what I am talking about. You pick first off the shelf non-ECC stick, it will be faster stick due to lower latency. You pick ECC stick, it will be slower, conservative timing stick. I just said that in my post.
Conservative timings create lower performance, with much bigger impact than just enabling/disabling ECC processing logic.

That being said, non-ECC sticks have interesting characteristics: lower, more aggressive timings which create more bit flip errors.. And additionally that stick have no ECC to fix it. Meanwhile ECC stick have rock solid timings AND error correction logic. I much more prefer the ECC ones.. Stability over speed in this case!

[AdrianBc]

Out-of-Band (OoB) ECC adds a >= 25% price premium to DDR5 DIMMs, because you need one extra DRAM chip for every 4, in order to provide 8 bits of ECC for every 32 bits of data. In mass-market products, such a cost is nontrivial.

While it is true that most ECC UDIMMs that can be found now have a 25% overhead in capacity, the DDR5 standard allows either 40-bit channels (25% overhead) or 36-bit channels (12.5% overhead).

For instance Micron makes ECC UDIMMs with 12.5% overhead. Other manufacturers, like Samsung, have chosen to make modules with 25% overhead because it is cheaper for them to do so, by using the same x8 chips used in non-ECC modules.

So when a vendor chooses to sell you a module with 25% overhead, because that is cheaper for them, they certainly do not have any ground to demand a price that is 25% higher.

I have also believed this myth about the 25% overhead of DDR5 ECC, until reading the actual standard, where it is shown otherwise.

[piorunz]

This is the most ignorant thing I've read in a while. What's scary is how confidently you proclaim it.

No, you just misunderstood my post. And if my simple post shocks you, you haven't been reading any internet lately it seems.

ECC UDIMMs only differ from non-ECC UDIMMs in terms of the number of DRAM chips on them. The DRAM chips, themselves, are exactly the same as the type used on non-ECC UDIMMs.

So, why the higher latency spec? That's only because they used conservative timing and adhere strictly to JEDEC specifications. They also tend not to have heatspreaders on them, like you often to see on "gaming" DIMMs. So, I'm not sure how much the specs are down to reducing heat dissipation or power consumption.

That's exactly what I am talking about. You pick first off the shelf non-ECC stick, it will be much faster stick with low latency. You pick ECC stick, it will be much slower, conservative timing stick.
Conservative timings create lower performance, with much bigger impact than just ECC processing logic.

That being said, non-ECC sticks have interesting characteristics: lower, more aggressive timings which create more bit flip errors.. And additionally that stick have no ECC to fix it. Meanwhile ECC stick have rock solid timings AND error correction logic. I much more prefer the ECC ones!

[AdrianBc]

It's got on-die ECC as standard, but not ECC all the way to the CPU.

The on-die ECC just brings the reliability to the same level as in the older non-ECC memories.

It does not offer any of the benefits of ECC memories, like protection against electrical noise or oxidized sockets and detection of memories that become defective after aging.

[AdrianBc]

I have often wondered, if I should begin to use ECC RAM for my NAS/server running 24/7. However, I have not really realized any issues being due to RAM errors.

Does anyone have any experience with running ECC RAM? Do you get errors/corrections reported in your logs regularly or at all? Is it really necessary in real life?

The most important advantage of ECC is that it detects the aged memory modules.

When the DIMMs are new, they may have a couple of errors per year that might not influence anything.

After a DIMM has been used 24/7 for some years, many of them will begin to have frequent errors, even multiple errors per day.

Without ECC, you will discover this too late, typically by noticing corrupt files that might be irreplaceable.

With ECC, you will be notified immediately and you can replace the offending module, so that the server or workstation may continue to be used without problems.

[AdrianBc]

Are there any consumer motherboards that support ECC on AMD 7000 series? I run a homeserver with a 5950X and Asrock B550M pro4 supports ECC without issues. But apparently the newer 7000 series mobo's do not support it by default?

Last time when I have looked ASUS had the most motherboards with AM5 ECC support.

This is a change, because in the past ASRock had ECC support on all motherboards, but now many of their MBs no longer mention ECC support.

The one that I would choose for a server or workstation is ASUS PRIME X670E-PRO, because it has the best expandability through PCIe slots, allowing for instance to have a GPU and one or two dual-port 10 Gb/s or 25 Gb/s network cards.

When less connectivity is needed, there are many other cheaper boards.

[Anux]

That's nice but you get no reporting. For all you know you could have a broken module that is spewing 1-bit errors on a constant basis and next thing you know you get a 2-bit error and wrong data - again without that fact being disclosed to you. In a way this in-module-only ECC functionality is worse than no ECC.

That's because it isn't some kind of optional error detection but a "needed to operate probably" thing. Like on hard disks where data couldn't be read or written error free without some ECC.

[coder]

Just a quick protip: you can typically find out if a given motherboard supports ECC by just downloading the PDF manual and doing a search for the likes of "error" or "ecc" or "e.c.c" (yes, without the final period to make sure they didn't derp up)

100% of examples I've seen that support ECC will say "ECC", somewhere in the specs. No need to search for the other variations.

Also, check their qualified memory list. If the board provides ECC support, they will most likely include some ECC DIMMs among those they've tested and vouch for.

[coder]

It is time to make ECC mandatory, there is little reason left not to do it and you can always turn it off if you do not want it.

Out-of-Band (OoB) ECC adds a >= 25% price premium to DDR5 DIMMs, because you need one extra DRAM chip for every 4, in order to provide 8 bits of ECC for every 32 bits of data. In mass-market products, such a cost is nontrivial.

Intel has been pioneering a different avenue, for some of their embedded products. They refer to it as in-band ECC, and essentially it works by setting aside a block of the address range to hold the ECC bits used to protect data in the rest of the RAM. This incurs a performance penalty and reduces the available memory capacity, but doesn't add cost and works with any (otherwise-compatible) DIMM.

Anandtech benchmarked a system with IB ECC enabled & disabled, in order to quantify the performance impact. Unfortunately, because it's Intel, they are playing their usual market segmentation games, rather than making this feature available on their entire range of client & embedded CPUs.

https://www.anandtech.com/show/18732/asrock-industrial-nucs-box1360pd4-review-raptor-lakep-ecc