X670E TAICHI RAM Issue

MB: X670E Taichi (Bios v1.04)
CPU: AMD RYZEN 9 7950X
RAM: G.SKILL TRIDENT Z5 DDR5 6000 32GB x 4
GPU: None
Storage: SAMSUNG 980 PRO 2TB x 2

I am trying to use the full 128GB RAM capability of the motherboard using 4 identical G.SKILL sticks (F5-6000J3040G32GX2-TZ5RK). I believe these are the recommended sticks for the new AMD 7950X CPU I am using. If I use all 4 sticks the MB wont post and Dr. Debug hangs on A6. However, I have tested each stick individually in slot B2 and each combination of 2 sticks in slots B2 and A2 with no issues (full windows boot). The XMP DDR5-6000 profiles load correctly and the correct timing are active (CL30-40-40-96) whenever I do any 1 or 2 stick combination. The only issue is when I attempt to boot with all 4 sticks which makes me think it is a MB issue. I have given it over 15 minutes to post to bios multiple times with all 4 sticks and it never does.

Quick Update: I updated the bios to v1.07 and now I can boot with all 4 RAM sticks at and autodetected DDR-5 3600 (underclocked) profile, but trying to enable the XMP profile results in a C5 error code hang.

Remember XMP = overclocking the RAM. there are no guarantees it will work.

Four modules don't run well at all with DDR5, that's how it is on Intel at least, where we have the most experience with it. I explain this in detail in my RAM thread (see signature) under 2).

With AMD AM5 boards and 7000-series CPUs, there are almost no empirical values apart from reviews, and user reports are just starting to hopefully come in from people like you trying it.

The first sign that four modules is not advised with DDR5 is that there are no four-module RAM kits available at all, and that's for a reason. Once you use four modules with a DDR5 board (also from other brands), the maximum frequency that the memory system can reach drops down considerably. With four dual-rank 32 GB modules such like yours, there is a huge drop in the attainable frequency, because the signal quality seems to suffer dramatically.

They might be able to improve the situation somewhat with a new BIOS, but not substantially. I would say that with the current generation of DDR5 board designs, with four modules, it's more likely that the frequency you can reach will stay quite low. With DDR5 it's always highly advised to use two modules only (and even with DDR4 that is advised, but four modules can at least work decently there).

DDR4 is actually better for high-capacity/high-density memory configurations, because:
- It doesn't experience such a drop in the electrical properties of the memory system when using four modules
- Big DDR4 modules and kits of four are readily available for a much lower price
- Four-module kits are actually certified on the QVL at MSI
- They will most likely outperform their DDR5 equivalent due to DDR4's lower latencies, when compared to DDR5's necessary low required frequencies at this configuration.
This is because the overall higher DDR5 latencies can't be compensated for by higher RAM frequencies anymore, because using four DDR5 modules requires lower frequencies to be stable.

As for the RAM performance scaling, read here, https://www.techpowerup.com/review/ddr5-memory-performance-scaling/

So, the board specification is not to be taken lightly. Even looking at two modules only, DDR5-6200/6400 kits are really causing some problems on boards with four RAM slots. That's on the upper end of what the signal quality currently allows for on DDR5, unless you pump in ungodly amounts of voltage or use other tricks that are not the best for a daily system. Watch this spot in the video here where an experienced RAM overclocker talks about that issue: https://www.youtube.com/watch?v=alk3QLyQebs&t=238s.

And then there's the video DDR5 motherboards should come with only 2 dimm slots as standard (Youtube)

DDR5-6400 and higher might only work properly on boards with two RAM slots, because the signal quality is better there than a four-slot board with two empty slots. And it also depends on the CPU's IMC (memory controller). But with four modules, you cannot dream to get anywhere near such RAM frequencies, you are lucky when it runs stable at a lower frequency somewhere in the DDR5-4800 range or so.

Yes, that comes on top of that. You are an early adopter of a brand new platform, which is also AMD's first foray into DDR5 technology. From what i hear, it's not the total catastrophy that it was with the first Ryzen generation where people were having issues left and right and begging for new BIOS updates to solve the most annoying things. But you can't expect smooth sailing either for the first weeks and months.

There are just the first early adopters reporting back to the board manufacturers about BIOS issues and lack of RAM optimization, so the improvements based on user feedback are just slowly picking up some steam. With any totally new platform, you will see rather big improvements being made in the first couple BIOS updates.

However, even on Intel 600-series, there still are issues with XMP support once you get to DDR5-6000 (and certainly above), as well as being restricted to lower frequencies when using four modules. The Z690 boards have almost a year of BIOS updates under their belt, but some fundamental limitations about the early DDR5 technology obviously cannot be solved completely.

Anyway, if you expect zero problems, then you can't be an early adopter, you have to wait at least a few months for the first few BIOS updates to have ironed out the worst annoyances. If you want the latest and greatest tech right after it was released, you're gonna have some "bananaware" that slowly ripens over time.

And i'm not even sure they can ever get DDR5-6000+ working flawlessly with four high-capacity dual-rank modules. This might be too much to ask for the first generation DDR5 solutions.