ECC options

I am running 3950X and Aorus Pro mobo.

It seems that my motherboard supports ECC memory

  • Support for ECC Un-buffered DIMM 1Rx8/2Rx8 memory modules

Are there any possible caveats when choosing the memory? I am looking at maxing out my system with 128GB ECC.

Realistically I guess we are looking at stock speeds and forget all about overclocking the memory.

You can probably raise the clocks and tighten up the timings some. I’ve read about many successes getting 2,666 ECC up to 3,000.

I haven’t bothered on mine. I played around with it a little bit but it’s back at 2,666. It seems fast enough and the whole tweak, reboot, hope and test thing gets annoying fast.

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I will try at first to see how stable my current non-ECC memory is at stock, forgetting about gaming. It really seems like that actually doing the actual work on machine is the only way to ensure the stability.

But I wonder how robust would 3950X system be with 128ECC memory? My mobo QVL list doesn’t really env mention about such scenario. I guess there is never any guarantee when you are building your own system.

Ahh I feel like I was better of leasing a Thinkstation at this point.

By the way, what does this mean?

  • Support for ECC Un-buffered DIMM 1Rx8/2Rx8 memory modules
  • Support for non-ECC Un-buffered DIMM 1Rx8/2Rx8/1Rx16 memory modules

Does neither signify a maximum capacity per stick? I sure hope not

1R means 1 side ranked. So only one side of the pcb has chips on it. You also got 2R, so both of the sides have chips on them. This provides a little benefit running 2 dimms, 2 dimms 2R is a little bit of extra bandwith. Running 4, 2R dimms is harder for the memory controller, than running 4, 1R dimms.

Memory chips have different configurations, internally. You can make 8GB dimms with 16 or 8 chips generaly. Or 18 and 9 with ecc. So 1 sided or 2 sided. But your want to go maximum capacity, so you can’t choose which chips and how many sides. It is going to be 2R and 18 chips in a certain configuration.

Micron has 3200MTS unbuffered ECC memory modules. But I think the official specification of the 3950x is that it can’t run 4 dual sided dimms at that speed. But I have to look that up. Unofficially I think it will work, maybe a little manual work setting some timings.

Found it on a unofficial website:
Memory Configurations
Dual Channel Single Rank
2 DIMMs DDR4-3200
4 DIMMs DDR4-2933
Double Rank
2 DIMMs DDR4-3200
4 DIMMs DDR4-2667

Here are some different type of modules you can choose from:

If you want to be safe you can run it a 2667MTS, AMD says it should work out of the box. You probably wont notice a difference in the real world with 3200MHz.

You can also run 3200MTS dimms @ 2667MTs, be sure to check if your motherboard sets the timings to 19-19-19-*.
Or you can try to run it at 3200MTS. There are 64GB 3200MTS (4x16GB Dual sided dimms) on your motherboards memory list. But I think 128GB is more demanding.

1R = single sided = SS
2R = double sided = DS

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