DDR5 4 dimms on am5 -- what's working, what's not?

Are you running 4 dimms on the AM5 platform? What about LGA1700? Post a pic and details of your setup!


I’ve been testing the new VSOC/agesa changes from AMD and 48gb dimm support. I am happy to report 96gb @ DDR5-6000 (2x48gb) is working great!

I’ll have a video about that soon.

I’ve been trying a lot of mixed (and non-mixed) configs of 4 DDR5 dimms and it seems to be the case that only 4x16gb will post fairly reliably, and only @ ~ 3600

Test Boards:

ASUS X670e Hero
Gigabyte B650E Master
Gigabyte X670 Elite AX
ASRock Taichi X670E
MSI Mortar B650 Wifi

TODO: More later

Working 128gb @3600

Working 160gb (2x48gb + 2x32gb)
Working 192gb (4x48gb)

There are THREE voltages that apply here: VDD I/O, VSOC and VDDQ. Mostly its not about the VSOC? But it can be a bit.

12 layer board – generally way better here than less than 12 layers when we’re talking about what we’re doing in this thread.

Remember from our video we saw stability with VSOC at 0.960 volts in some cases!

Understand the stability here is really a recipe between board, cpu, memory kit, the specific dimms you have, temperature, how they’re seated in the slots and a bunch of really minor variables. (Don’t be afraid to reseat your memory! There can be more variance between individual modules in 4 “identical” kits than most people realize.)

For me the secret to getting 4 dimms on AM5, and stable, was as follows:

  1. Boot the system with 2x48gb dimms. go into bios. Set the Dimm voltage what the kit requires (usually on the label)
    1a. You may need to set the VSOC to 1.2 volts. Or 1.25. Do not set expo or mess with the clocks – leave everything on board defaults.

  2. Save and exit bios. Shut the system down normally.

  3. Install the next two dimms

  4. Wait patiently for the auto-train process. On the taichi it took more than 8 minutes (!) with 4x48gb dimms.

  5. (optional) If you want to dial in the specs further, working on timings, frequency and termination for further speed is possible, if you are very patient.

Prime 95 is an excellent choice for checking stability. Your memory may need active cooling! Memory at this density can show signs of instability with a surface temperature of more than 60c in my testing – especially jedec kits that are rated for more than 5000 (that may actually be running less than that since you are running

* If that doesn’t work, you can pop two dimms out and set VSOC to 1.3 volts or up your DIMM voltage 0.05 volts. But please! *

Don’t treat VSOC as the only knob here – it’s most often not really the right knob, or only knob, you need for actual stability

You “can” mix dimms in channels – this can have better performance BUT for stability in mixed dimm configurations putting like dimms on a channel is likely to be more stable and also actually post.

There are a lot of scenarios where… the am5 system simply will not post.

It is generally recommended, I would say/imho, to disable memory context restore.

Are you using 4 dimms? Can you post what its running at, and what kit(s), what board? Post pics of your setup :smiley:


128GB@5600 with tight timings. They are 2 Kingston 2x32GB CL36 expo kit, Hynix-A dies.
It is 24/7 stable.

Below is a test run at 6200MHz. It is only screenshot stable.
The trick is to configure bus termination manually, as circled below.


Asus x670e-f

4x16gb ddr5 6000 cl30 (microcenter purchase, teamgroup brand) so 64gb total

I literally just set XMP and it runs full speed no problem. Motherboard takes a long time to boot because it does the memory training every boot. Which I don’t mind at all, since I’m not anal enough to cry about boot times. And I grew up through the 90’s with slow booting computers…

Dunno voltages, I literally just hit xmp profile and away I went…

FSB:DRAM is 1:30
CL 30
tRCD 36
tRP 36
tRAS 76
tRC 146

apparently they are sk-hynix chips.

I notice sometimes when people populate all 4 slots, they install their ram 1-2-3-4 meaning technically you get mismatched pairs. I made sure kit one was 2-4 and kit two was 1-3 which would be their proper matched pairs. Again lot of people just go 1-2-3-4 so each channel is technically getting non matched chips.

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Actually, 1-2-3-4 is the correct way. With 4 dimms, you have to put the same model/kit on the same channel. I was running Hynix on one channel and Samsung on the other channel for a month. Some intel boards even allow you mismatch voltage and timings for different channels.

What? Lmao

Left to right the slots are A-B-A-B. When you run only one kit, you install into both B slots. As they are paired. So if you install your ram 1-2-3-4 your first kit will be split A and B instead of matching them into AA or BB… So you are wrong.

@jxdking is correct, if you can’t get a matched kit of 4, it is best to put each 2 dimm matched kit to a specific channel, which in this case would be 1-2 (channel A) or 3-4 (channel B).

interesting fact: when placing in only 2 dimms on a 4 slot board, the furthest slots per channel are preferred to cut down on signal reflections.

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Can confirm. This is correct for mismatched dimms.

I should neckbeard for just a moment here, though. You can run mixed dimms in a channel and this may be better for performance to do with rank interleave calculations. HOWEVER this is much more likely to actually post. It also might not have a performance penalty. But then it might.

TBH, intel’s document is way better than AMDs.

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I am not sure I understand, if you are going to the trouble of using 4 high capacity DIMM’s, why would you mix & match instead of just getting a single 128GB or 192GB kit?

Gonna take a shot in the dark and say he couldn’t get his hands on 2 matching kits

4x48GB is in stock CORSAIR Vengeance RGB 192GB (4 x 48GB) 288-Pin PC RAM DDR5 5200 (PC5 41600) Desktop Memory Model CMH192GX5M4B5200C38 - Newegg.com

We are testing both matched and mismatched configs. I think its likely some of our audience has 2x16gb already and might contemplate the upgrade to 2x48gb for a nice even 128gb but… what do you give up by doing so?

I was on 2x32+2x16 configuration.
I feel the bandwidth is not consistent. The first 64GB gets full bandwidth just as dual channels. The last 32GB essentially runs at single channel. Those are my observations based on the speed of memtest86’s progress bar. Memtest86 slows down once it passes 2/3 of the progress.

I was chatting on background with “actual” engineers working on this earlier and they suggested that each stick type in its own channel, while maybe more stable, is a potentially slower config than if it can work with each dimm type in a channel. That may not work, or may be worse overall performance, depending on how badly they’ve been mismatched.

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Even with the latest Bios 1410 my B650 Creator sets the voltages in auto mode with DOCP profile way too high.
1.4V for CPU VDDIO MC and 1.3V for CPU SOC, which is then according to Rytzen Master 1.35V SOC and 1.45V MC.
With such high voltages, I couldn’t set UCLK=MEMCLK 1:1 at 6000MT, but it works stable at 1.2V for SOC and MC.

I can recommend the 96GB Kit from G.Skill - F5-6400J3239F48GX2-TZ5RS, with a little bit work you can run them at 28-36-36-50 and tight secondary timings at 6000MT


I just noticed asus updated the QVL for the proart x670 board (and probably others too). It now features 4x32 configs at 5200 CL 40 and also some 2x48 configs…

running 4x16gb g.skill ram in my am5 B650 AORUS ELITE AX but getting sub jdec speeds with updated bios, i use to get stable 6000mhz but i suspect the voltage was through the roof. I have manage to get above the listed speeds in the images below but i get IRQ memory errors within 5-10 minutes.


thing is these are only primary timings.
you want something that shows all the timings you have access to in the bios memory settings in bios/uefi
hwmonitor is a good start.



sorry bud posted the wrong link. but it looks like you found the app anyway. :wink:

also these are the auto/default timings, anything else is either 5 mins till BSD or wont even post.

ryzen timing checker gives me a fun error of this

However zentimings gives me this

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I would be surprised if Samsung sticks even works with 2 sticks at EXPO.
I experienced 2 Samsung based kits. Neither of them worked as the specification with AM5.