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ECC and DDR5

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Re: ECC and DDR5

#61

Post by Havoc »

Aurornis wrote: post #40
Havoc wrote: post #5

Got ECC udimm for my ddr4 server and was surprised to see it picking up errors occasionally (once every couple months). Likely from a weakness in one of the sticks. This far it’s always corrected it though so opted to keep them anyway (nobody wants to be minus 32gb in these trying memory times) With normal sticks I’d not have know that there is a potential issue.

There should not be errors during normal use at rated speeds. With non-ECC RAM running a memory test and getting any errors means it’s not stable. The memory tests run at maximum bandwidth constantly so a few days of full bandwidth memory testing might produce as many transmissions as your months of regular server use. Seeing bit errors (even if corrected) means something is not right. The ECC can correct it for a wh…

Alas this is white label mem off eBay and fair bit of time has elapsed so not confident exchange would work. Minor miracle the ECC works at all given that

At some point I should try running it at slightly lower speed i guess. It’s very hard to troubleshoot something that only happens every month or two though

Never seen it fail a memtest but I can see it in the ECC stats since those cover weeks/months.

Re: ECC and DDR5

#62

Post by wmf »

gruez wrote: post #54
graemep wrote: post #6

Earlier quoted context omitted.

> ECC RAM is not needed for every application and mandating it for every gaming rig and machine used to run Chrome will just increase prices unnecessarily. The price increase will be very small if manufacturers are no longer able to segment the market to make a higher margin on those who need it. No one wants even games or web browsers to crash randomly. > If they want to eat that cost, it should be up to them. They…

>The price increase will be very small if manufacturers are no longer able to segment the market to make a higher margin on those who need it. AMD doesn't have this segmentation. Where's the hoard of people building systems with ECC ram? At best you have a few people on HN saying they're doing it, but in practice nobody actually does it.

ECC UDIMMs are crazy expensive, presumably because they don't have economy of scale. Mandating ECC would solve that.

Re: ECC and DDR5

#63

Post by justsomehnguy »

Wowfunhappy wrote: post #21
zargon wrote: post #18

Earlier quoted context omitted.

This is the attitude that needs to change. If RAM is 25% of the system cost (say for a home server in your example), then the cost for ECC is 3% of the system cost. There is no world where accepting data corruption in order to save 3% cost is a reasonable tradeoff. ECC should be standard, period.

When I last looked at this (a couple of years ago), it wasn't just the cost difference—the ECC memory available to purchase was also slower than non-ECC offerings, or at least cost significantly more if I actually wanted the same speed. At least for me, going ECC simply didn't make sense. Caveat that I was building a gaming PC at that time, I might have gone differently for a home server. And, this was before the mem…

The same reason your utility trucks isn't rated for 200KM/H speeds.

Re: ECC and DDR5

#64

Post by zargon »

Havoc wrote: post #61
Aurornis wrote: post #40

Earlier quoted context omitted.

There should not be errors during normal use at rated speeds. With non-ECC RAM running a memory test and getting any errors means it’s not stable. The memory tests run at maximum bandwidth constantly so a few days of full bandwidth memory testing might produce as many transmissions as your months of regular server use. Seeing bit errors (even if corrected) means something is not right. The ECC can correct it for a wh…

Alas this is white label mem off eBay and fair bit of time has elapsed so not confident exchange would work. Minor miracle the ECC works at all given that At some point I should try running it at slightly lower speed i guess. It’s very hard to troubleshoot something that only happens every month or two though Never seen it fail a memtest but I can see it in the ECC stats since those cover weeks/months.

If you bought it from one of those ebay outfits that specialize in memory modules, they also often offer a lifetime warranty. Usually those sellers put their own sticker on the module. Worth a check.

Re: ECC and DDR5

#65

Post by jmb99 »

Wowfunhappy wrote: post #21
zargon wrote: post #18

Earlier quoted context omitted.

This is the attitude that needs to change. If RAM is 25% of the system cost (say for a home server in your example), then the cost for ECC is 3% of the system cost. There is no world where accepting data corruption in order to save 3% cost is a reasonable tradeoff. ECC should be standard, period.

When I last looked at this (a couple of years ago), it wasn't just the cost difference—the ECC memory available to purchase was also slower than non-ECC offerings, or at least cost significantly more if I actually wanted the same speed. At least for me, going ECC simply didn't make sense. Caveat that I was building a gaming PC at that time, I might have gone differently for a home server. And, this was before the mem…

There are absolutely fast DDR5 ECC DIMMs[1]. Just break out your wallet (and piggy bank, and rainy day fund, and..)

The main reason there aren’t more options here is that a) high-frequency memory usually isn’t sufficiently stable, unless binned, and b) there’s very, very, very little demand.

[1] https://v-color.net/products/ddr5-ocrdimm-amd-wrx90-workstat...

Re: ECC and DDR5

#66

Post by hnuser123456 »

adrian_b wrote: post #43
aidenn0 wrote: post #41

Earlier quoted context omitted.

Besides electrical noise, there are mechanical issues as well. I've seen systems fail memtest86+ after being moved, and the issue being fixed after reseating the DIMMs. ECC can catch mis-seated DIMMs very quickly.

The mechanical issues also act through increasing the sensitivity to electrical noise. The imperfect contacts are equivalent to adding series resistors, possibly in parallel with parasitic capacitors, on the link traces, allowing a greater amplitude for the noise pulses.

In addition to reducing the energy content of the actual desired signal.

Re: ECC and DDR5

#67

Post by jmb99 »

adrian_b wrote: post #25
Wowfunhappy wrote: post #21

Earlier quoted context omitted.

When I last looked at this (a couple of years ago), it wasn't just the cost difference—the ECC memory available to purchase was also slower than non-ECC offerings, or at least cost significantly more if I actually wanted the same speed. At least for me, going ECC simply didn't make sense. Caveat that I was building a gaming PC at that time, I might have gone differently for a home server. And, this was before the mem…

Yes, ECC DIMMs are available only for the memory speeds guaranteed to work by the manufacturers of CPUs, like Intel and AMD, e.g. for up to DDR5-5600 in UDIMMs or DDR5-6400 in RDIMMs. The "gaming" DIMMs are available in much greater speeds, which are "overclocked" speeds, i.e. there exists absolutely no guarantee from Intel or AMD that they work at the advertised speed, even if they frequently do work. However, with…

> ECC DIMMs are available only for the memory speeds guaranteed to work by the manufacturers of CPUs, like Intel and AMD, e.g. for up to DDR5-5600 in UDIMMs or DDR5-6400 in RDIMMs.

This is not true[1]. These DIMMs are not guaranteed to work with all Threadripper CPUs, but they are guaranteed themselves to be stable at their advertised frequencies, which are higher than JEDEC. (And from my experience, 9000-series threadripper is perfectly happy to drive 8-channel 1Rx8 at 7200MT/s.)

AMD (and possibly Intel, I don’t have any experience with their recent offerings) also lets you overclock memory completely on WRX90. So if you buy JEDEC sticks, you’re welcome to try to push them as hard as you can.

[1] https://v-color.net/products/ddr5-ocrdimm-amd-wrx90-workstat...

Re: ECC and DDR5

#68

Post by jmb99 »

exabrial wrote: post #31

> We need ECC RAM to be more widely used. Ideally we would have some government action to force this given the ongoing cost.... The rest of this article is great. This, however, is absolute garbage and nonsense. The last thing you want is more regulations and "government certified systems". Take a look at the bullshit with age verification bills and operating systems.

How is “all RAM sold in consumer PCs must be registered ECC” equivalent to age verification laws? I’m not saying I agree with the premise but that is a bit of a leap

Re: ECC and DDR5

#69

Post by sandreas »

One thing I also did not know until recently was that there actually is ECC unified memory.

I noticed the difference because in a Hardware forum someone wrote that the framework desktop does not have ECC while an HP G2 Workstation also featuring the Ryzen 395 Max but in the ECC supporting variant paying a premium of +600 bucks.

Re: ECC and DDR5

#70

Post by undersuit »

adrian_b wrote: post #25
Wowfunhappy wrote: post #21

Earlier quoted context omitted.

When I last looked at this (a couple of years ago), it wasn't just the cost difference—the ECC memory available to purchase was also slower than non-ECC offerings, or at least cost significantly more if I actually wanted the same speed. At least for me, going ECC simply didn't make sense. Caveat that I was building a gaming PC at that time, I might have gone differently for a home server. And, this was before the mem…

Yes, ECC DIMMs are available only for the memory speeds guaranteed to work by the manufacturers of CPUs, like Intel and AMD, e.g. for up to DDR5-5600 in UDIMMs or DDR5-6400 in RDIMMs. The "gaming" DIMMs are available in much greater speeds, which are "overclocked" speeds, i.e. there exists absolutely no guarantee from Intel or AMD that they work at the advertised speed, even if they frequently do work. However, with…

So as I was overclocking my AMD Ryzen 7 2700 I discovered that the Infinity Fabric has ECC because if I tried to run my fancy DDR-3466 ram at full speed I started getting logged errors from it. Those failed transactions slow down the system because the data needs to be corrected or even re-sent. The RAM runs fine overclocked at DDR4-4200 in a newer system, but my old Ryzen 7 2700 couldn't handle anything past DDR4-3266 without the errors creeping in.

Without the reported ECC on Infinity Fabric I would have had no idea that the errors were happening and affecting performance.

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