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Comment by Havoc | Hacker News Reader

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.

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You should be able to get the stick replaced under warranty. Every memory manufacturer I have ever seen has a lifetime warranty. As long as you RMA it before replacements become unavailable.

Depending on your server's CPU sockets, reseating the CPU might help if they were ever swapped before (esp if you got the server used). I have a marginally bad RAM slot on one of my Supermicro X11 boards because my dumb ass dropped the CPU into the socket and bent a few pins. I bent them back, but you can only do so much and the furthest RAM slot won't work without throwing errors daily if I run it at 2400MHz.

I have a HP Z640 that only has 3/4 DIMM slots working. Reseating the CPU didn't help and the same CPU works perfectly in another Z640. I never found out the cause. It was sold as "unknown condition for parts" so $50 for a server that works perfectly apart from one DIMM slot is still a good deal.

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 while but I would want to RMA that stick if it’s in warranty.

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.

That was true in DDR4 but I understand DDR5 has pushed density so far that you do get errors in normal modules - like early LCD panels that were expected to have a few stuck pixels - and therefore ECC should really be mandatory.

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