Fast 48GB DDR5 ECC UDIMMS?

I gather that 48 GB is the largest size currently available in DDR5 ECC UDIMMs. Does anybody know who sells the fastest such modules? I’m trying to get a rough feel for the absolute maximum achievable memory bandwidth with ECC on AM5 assuming 96GB+ of memory is a hard requirement. I’ve looked around but wasn’t able to find anything above 4800 MT/s.

I’m interested in AM5 as a “workstation-lite” platform rather than for gaming.

Thanks!

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I’m currently running 96GBs ECC at 5200MT/s on two DIMMs on my AM5 system. It was nemix branded and rated for 5600MT/s but the rest of the system can’t go that fast.

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NEMIX seems like a bit of a hit or miss, Kingston also offers 5600MT fwiw.
KSM56E46BD8KM-48HM

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Which dies are those?

Kingston uses Hynix dies which are by far the best ones for overclocking. Those are the same dies as the 6400/6800/… non-ECC kits use. So look for any modules using those dies. As always on AM5 you’ll be CPU/IMC limited and running ECC might be a bit harder so you might not quite get it to 6000-6400, but Hynix dies give you the best chance.

It’s using 24Gb Hynix M-die, which is the best on the market at the moment (not to be confused with 16Gb M-die which were so-so).

The PCB seems pretty high quality, looking at it close up I think its a 10 layer board.

Hmm, it’s a bit surprising Hynix can only do 5200… Bad luck with IMC perhaps. My non-ECC hynix 96 GB kit can do 6200 in 1:1 or 6600 in 1:2 modes. Don’t know how ECC influences the IMC but I would be surprised it is a 1000 MT/s gap.

I thought it was Crucial. I know only about 3 companies make the chips on the dimms so it would have to know the rating of the particular dimms you are looking for.

It’s my motherboard limiting me on memory speed, It doesn’t allow any memory overclocking.

The big three are Hynix, Micron and Samsung. Hynix seem to be the best at OC for 24Gb dies, with Micron not too far behind, I’m not sure how Samsung is doing but I’m under the impression they are in last place by a wide margin.

I thought he was asking which brand. I don’t know if you can actually search for Hynix branded memory thats why I said Crucial Memory. They have a good interface to order the exact kit you want.

ohh I see what you are saying. I don’t think Nemix actually specified what memory dies they used on their website. Kingston does but it is subject to change with production runs, even though the memory retains the same part number after they switch memory dies.

I believe Crucial memory always uses Micron dies.

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Source? I’ve never seen that occur without Kingston changing the model number

Support explicitly told me this during an RMA I had with them, there is a revision number that follows the naming convention #######-###.X##X somewhere on the label of the DIMM that can be used to identify the revision, however there’s no way for you or I to look up what revision numbers correspond with what components are being used.

I am using 48GB 5600 MT/s ECC UDIMMs on EPYC AM5

is what I’d say if USPS didn’t lose my RAM I ordered just after Christmas

And now there’s a fire where I bought it so…yeah

That sounds like something that’s valid for their consumer line where it’s not specified such as the KVR series. https://www.kingston.com/datasheets/KVR48U40BS8-16.pdf (example)

It was a KVR series kit that this component switching issue came up; Kingston had to match the revision number of the kit I was RMA’ing to the other kit’s revision numbers I was running since it was installed in a quad socket system and mixing and matching component vendors was not advised.

If Kingston puts the brand of the components in the datasheet I would trust that they don’t change, but it seems they do not for most of their SKUs.

I don’t see how this would affect anything though as long as you run the components in spec for which they’re certified for.

In theory it shouldn’t, but in practice it does.

I found an example of basically the same Kingston memory, but one of the SKUs actually specifies all the components in it:

vs

The KSM48R40BS8TMI-16MDI part number actually has all of it’s components specified while KSM48R40BS8-16MD doesn’t; so it’d be safe to assume you could get different components in KSM48R40BS8-16MD unless you had matching revision number modules.

Right. I know they also grade them which affects the price too. I just hope they don’t try to jack up the price again. The memory manufacturers like to do that sometimes

I’m using 2x Kingston KSM56E46BD8KM-48HM (96GB 5600 CL46) on an Asrock Rack AM5D4ID-2T BMC. You can go a bit tighter with latency even on SPD voltages or bump the vdd and go on much higher speed if you like. Typical hynix-m dies with ecc bits enabled.

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