Can ECC RDIMM support be enabled by firmware? - Page 1
Forum section: electronics / general

author: hinofi
author_rank: Newbie
timestamp: April 18, 2020, 01:17:07 pm
content: This question may seems stupid, because myself also believed that while some CPU/chipset can use ECC RAM by some software modding, RDIMM will need specific circuit to support.However I randomly saw a comment under this video:https://youtube.com/watch?v=dLkWB-Iw3-s(The video itself is not related to my topic, I put it here just for reference) which says: "......it's meant for budget PC with a i3 8100, g4560, G5400 with ECC REG DDR3 (yes, your board dose support) since they are as cheap as rubbish in China......And BTW, almost every DDR3 MB can do ECC REG support too, also a little mod of the BIOS will do......"I knew there might be some weird things going on in China, but this one is hard to believe. Is that true, or he is just another bull-shitter?

author: wraper
author_rank: Unknown
timestamp: April 18, 2020, 01:43:01 pm
content: Quote from: hinofi on April 18, 2020, 01:17:07 pmNone of them support registered RAM.

author: senso
author_rank: Frequent Contributor
timestamp: April 18, 2020, 01:46:34 pm
content: All those CPU's supports ECC, check on Intel Ark..https://ark.intel.com/content/www/us/en/ark/products/126688/intel-core-i3-8100-processor-6m-cache-3-60-ghz.htmlhttps://ark.intel.com/content/www/us/en/ark/products/97143/intel-pentium-processor-g4560-3m-cache-3-50-ghz.htmlhttps://ark.intel.com/content/www/us/en/ark/products/129951/intel-pentium-gold-g5400-processor-4m-cache-3-70-ghz.htmlAnd they all can run DDR3L, but the IMC won't live long due to the overvolt at 1.5v for DDR3L it will degrade overtime, with 1.8v for regular DDR3 dont expect it to last all that long.The mobos need to have extra traces between the CPU and the RAM slots, because they use a couple more data bits, as is expected.

author: wraper
author_rank: Unknown
timestamp: April 18, 2020, 01:51:26 pm
content: Quote from: senso on April 18, 2020, 01:46:34 pmECC and registered are two completely different things.

author: magic
author_rank: Super Contributor
timestamp: April 18, 2020, 09:07:35 pm
content: "Registered" means a buffer on the data bus which delays all transfers by one cycle. This has to be accounted for by the memory controller in the CPU for the whole scheme to work.If the CPU doesn't support it then it doesn't.There are instances of CPU features being enabled/disabled by poking undocumented registers, but unlocking RDIMM support is not something I have heard about yet.OTOH, unregistered ECC RAM is known to work on some motherboards which don't advertise such support. Apparently the designers simply monkeyed the reference design, including all the additional wiring required for ECC. Software-wise, they all use init code provided by the CPU vendor so no problem here.

author: wraper
author_rank: Unknown
timestamp: April 18, 2020, 10:22:48 pm
content: Quote from: magic on April 18, 2020, 09:07:35 pmThe issue is it's relatively rare and not cheap. There is no trick of buying cheap RAM pulled from servers. The cheapest option for non obsolete system with ECC is desktop Ryzen (with no iGPU) or Ryzen Pro APU (not sold in retail) + motherboard which supports unbuffered ECC DDR4 (AFAIK mostly from ASUS and Asrock).

author: wraper
author_rank: Unknown
timestamp: April 18, 2020, 11:27:22 pm
content: Quote from: hinofi on April 18, 2020, 01:17:07 pmBTW either you tell at which time in the video or it did not happen.

author: MK14
author_rank: Super Contributor
timestamp: April 19, 2020, 01:16:22 am
content: Quote from: wraper on April 18, 2020, 11:27:22 pmIt seems to be a youtube COMMENT. With the usual potential for complete and utter lack of factuality, that indicates.https://linustechtips.com/main/topic/1027361-this-chinese-motherboard-shows-intel-lied/?tab=comments#comment-12246224Quote

author: MK14
author_rank: Super Contributor
timestamp: April 19, 2020, 01:33:28 am
content: Also, I may have found one of the "articles", explaining how to do it.BUT, it seems the youtube commenter, seems to have misunderstood what it says.It is talking about UNBUFFERED ECC, which is completely different, to cheap (used) registered ECC.Also, he (or rather other(s), in later posts, NOT quoted here, so see link for details) seems to be saying that even using the unbuffered ECC, on unsupported hardware/cpu, is not viable, anyway.QuoteQuotehttps://superuser.com/questions/284442/is-it-possible-to-boot-a-consumer-i7-system-with-a-xeon-processor-and-ecc-memorytl;drIt is very likely to be a FALSE rumour. But with such unreliable information/sources, it is very difficult to 100% prove it to be false.

author: wraper
author_rank: Unknown
timestamp: April 19, 2020, 01:42:11 am
content: Quote from: MK14 on April 19, 2020, 01:16:22 amLOL, it's not even on youtube to begin with. But what's clear, contrary to what's claimed you can try modifying BIOS as hard as you want, but you won't even get even unbuffered ECC support on most desktop boards simply because there are no traces to additional RAM chip on PCB. ECC UDIMM will simply operate as usual non ECC RAM. Not to say exorbitant RDIMM support claim.

author: Monkeh
author_rank: Super Contributor
timestamp: April 19, 2020, 03:25:15 am
content: Quote from: wraper on April 19, 2020, 01:42:11 am.. yes, it is, that's a quote of the comment. It's right at the top if you just look at the video.But, yes, while the memory controllers fully support ECC (and probably buffered RAM, too, frankly - one design to rule them all), it's not likely to work on typical boards as they'll have intentionally not have fully connected the modules.

author: MK14
author_rank: Super Contributor
timestamp: April 19, 2020, 03:51:56 am
content: After much further searching, I found a (possibly the) youtube video, supposedly demonstrating the ECCregisteredmemory usage on a normal motherboard.Warning: It is dated, worryingly close to April 1st Fools day (March 28th).I am still rather/very sceptical.Anyway, he seemed to be using a Xeon cpu, which is one of the things you need to do, to support ECCregistered.So, the remaining thing would be the motherboard.Also, it was a fairly old processor/motherboard. maybe such an old one could/did support it, under some circumstances. It doesn't mean you can use ECCregisteredmemory, in general on non-server motherboards/cpus.https://youtu.be/OWcf1LP0z1k?t=541EDIT: Correction.It may still be UNBUFFERED ECC and still not registered ECC.I re-read my original source, for the video.Here:https://linustechtips.com/main/topic/631990-will-ecc-server-memory-work-in-my-x58-motherboard-asus-p6t/QuotePart where he definitely seems to state it is unbuffered ECC memory:https://youtu.be/OWcf1LP0z1k?t=60tl;drI think some people got confused, and thought he meant REGISTERED ECC, from reading the comments.I got confused for a while as well (because he keeps on calling it just cheap/'ECC').

author: Monkeh
author_rank: Super Contributor
timestamp: April 19, 2020, 04:20:16 am
content: Meanwhile, in modern CPUs: a Celeron G4900 (ECC), a Pentium Gold G5400 (ECC), a Core i3 8100 (no ECC), a Core i5 8400 (no ECC), and a Xeon E 2104G (ECC) are all essentially the same chip. Maaaaaaybe the mask set is different for the dual-cores (it probably is for the hex parts I didn't list), but it's the same memory controller, and I'll bet (and the Chinese apparently know) that it isn't locked. It's all just firmware.None of these officially support buffered, to my knowledge. I still wouldn't be surprised if the controller has it implemented just to avoid having to test more implementations with bits ripped out.

author: hinofi
author_rank: Newbie
timestamp: April 19, 2020, 03:25:16 pm
content: Thank you everyone!So basically the comment is just ranting to get attention, and what he said is highly unlikely, right?

author: Monkeh
author_rank: Super Contributor
timestamp: April 19, 2020, 03:48:37 pm
content: Quote from: hinofi on April 19, 2020, 03:25:16 pmModerately unlikely. Certainly hard to arrange and impractical on most if not all retail boards.