Where are the DDR5 ECC UDIMMs?

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Jan 3, 2023
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It is more complicated than that. See the long LGA 1700 Alder Lake "Servers" thread. There actually are 72 bit wide and 80 bit wide DDR5 ECC modules. It appears as if most, if not all unbuffered DDR5 ECC modules are actually 2x36 and not 2x40. The registered DDR5 ECC modules appear to be 2x40.
 

AlOX

New Member
Mar 30, 2023
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Feels like the we deserve some explanation from the big companies. It doesnt make sense that this info isn't published anywhere on the net. If I had to make a bet i would buy a 2x40 as the true ECC, but a couple 100$ bet isn't for me. Lean to wait for real clarification.
 

ddr5ecc

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Feb 5, 2023
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Kingston UDIMM ECC KSM48E40BD8KM-32HM

inside a Supermicro X13SAE 72 bit wide

inside a Asus WS W680 80 bit wide

but in Windows when you call the wmic command in a powershell both Mobo says "5" single bit error correction.
 
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Jan 3, 2023
55
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Feels like the we deserve some explanation from the big companies. It doesnt make sense that this info isn't published anywhere on the net. If I had to make a bet i would buy a 2x40 as the true ECC, but a couple 100$ bet isn't for me. Lean to wait for real clarification.
ECC modules have historically been 72 bits wide. It is only with DDR5 that we are seeing a 2x40 = 80 bit wide option. Both are "true" ECC. Both offer 1 bit correction. The confusion is around the reporting of errors (multi-bit detection). I also have a feeling the tools are misreporting things as well.
 

AlOX

New Member
Mar 30, 2023
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ECC modules have historically been 72 bits wide. It is only with DDR5 that we are seeing a 2x40 = 80 bit wide option. Both are "true" ECC. Both offer 1 bit correction. The confusion is around the reporting of errors (multi-bit detection). I also have a feeling the tools are misreporting things as well.
I think the on-die ECC secrecy made all this misinformation about unbuffered DDR5 ECC. Otherwise we would commonly know that a 80 bit is the standard for all.
Looks like a great paper about the subject.
 

RolloZ170

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Apr 24, 2016
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Otherwise we would commonly know that a 80 bit is the standard for all.
which is not the case. to match same 64+8bit(DDR4) we need just 2x 32+4bit(DDR5)
seems like some memory controllers do not use all the 8 bit ECC.
maybe some systems do not use the 2 banks and use one x8 (or two x4) chips for ECC.
 

ddr5ecc

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Feb 5, 2023
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13700K and Kingston KSM48E40BD8KM-32HM in an Asus WS W680 I get 'totalwidth' 80bit

13700K and Kingston KSM48E40BD8KM-32HM in a Supermicro X13SAE I get 'totalwidth' 72bit

datawidth.jpg


This is the screenshot from the X13SAE. In the other thread is a screenshot from the Asus board.

The Asus Board is good but you should have a normal DDR5-6000 memory at hand.

If you configure it in the wrong direction the easiest way to get it back to life is to pull out the ECC RAM and pull in the normal RAM and boot into BIOS and change some parameters.

I can't remember a Board where I had that much trouble to get things fixed.

And start with the BIOS version 2305 from the beginning - the earlier BIOS is even more P.I.T.A.
 
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LiKenun

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Nov 13, 2022
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Curious to know if anyone has spotted 48GB DDR5 ECC UDIMMs in the wild in part number catalogs yet.
And I just did.

https://www.smartm.com/api/download/fetch/81
  • SRI6G7UD5385MB — 48GB DDR5 4800MHz ECC UDIMM (−40 – 85 °C)
  • SR6G7UD5385MB — 48GB DDR5 4800MHz ECC UDIMM (0 – 70 °C)
Whether this works with consumer boards or not is a big question mark given that AMD’s Zen 4 platform is in a bit of a disarray currently.
 
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Styp

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Aug 1, 2018
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I am confused... (as usual).
I built a W680 + Kingston 2x 32Gb ECC workstation and Windows is reporting MemoryErrorCorrection 3.
I use the latest 2305 Bios - what am I doing wrong?

Mainboard is the Asus W680 one.

Screenshot 2023-05-28 102146.png