Memtest86 too slow in A2SDi-8C-HLN4F ?

[thomas-hn]

Hello,

currently Memtest86 is running in my new Supermicro A2SDi-8C-HLN4F with 256 GB of DDR4 ECC RAM.
I am not an expert with Memtest86, but I have the feeling that it runs a bit too slow on my system. Therefore, could you please double-check?

Motherboard: Supermicro A2SDi-8C-HLN4F
CPU: Atom C3758 (actively cooled by a strapped on fan)
RAM: 4x Samsung M393A8G40AB2-CWE

At this point I want to mention that Supermicro only lists the MEM-DR464L-IL01-ER32 (Samsung M393A8G40BB4-CWE (Link)) 64 GB modules in the officially supported RAM list. However, my distributor double-checked and told me that the Samsung M393A8G40AB2-CWE (Link) are 100% compatible. In another post "TrueNAS Mini X+ and XL+ maximum memory with TrueNAS 13" the user @awasb mentioned "256GB worked in the a2sdi-8c-hln4 over here with 4x Samsung M393A8G40AB2-CWE (64GB RDIMM ECC). But stream performance didn't scale up beyond 128GB (in my case), that's why I removed it (in late 2022) and stuck with 128GB.". So the modules seems to work generally in the board. However, I did not completely get the point about the performance.

The BIOS was updated last week to the latest version Supermicro provides (now I am aware, that upgrading might not be the best idea in all cases).
After the BIOS update I loaded the default settings. However, with those settings the system was not able to correctly run Memtest86 and the system completely freezed after a few seconds. In the post "256GB on Supermicro A2SDi-H-TF" I found that it is necessary in the BIOS to set „North Bridge“ ⇒ „Chipset Configuration“ ⇒ „Command Mode“ to the value „2N“. After this change I started Memtest86 and it is running since a bit more than 7 days.

Here you can see the current progress of Memtest86 and how long it took to get to this point. At the moment it is over 7 days for ~3.5 passes over the 256GB.
So if we say the 4 passes of Memtest86 are 400% and at the moment my system is in the 4th pass at around 41% the overall progress is around 341% of 400% in ~178 hours. If calculating a bit this means, that the overall test will take around 209 hours, or 8.7 days.
For comparison, when I did a Memtest86 on my other system (64 GB RAM and an Intel i7) the complete test took around 1 day and when scaling up, it would have taken 4 times this time for 256 GB of RAM, meaning around 4 days.
So it seems my A2SDi-8C-HLN4F is at around half the speed on its Memtest86.

Is this Memtest86 speed expected on a A2SDi-8C-HLN4F or should it be faster?
Do you have any recommendations what I could check?

If needed in any way, I have also attached a screenshot with some more details on the hardware.

Thanks a lot in advance,

Thomas

 

[Ericloewe]

It's quite possible that some tests take exponentially longer with larger memory pools, depending on how they're implemented. Annoying, but not worrisome.

 

[Etorix]

On top of that, these large modules may be somewhat slower than smaller modules. It's annoying that the four-pass test takes eight days to complete, but that seems whithin what could be expected.

 

[joeschmuck]

The speed of these tests is not based solely on the speed of the RAM, the CPU speed makes a huge difference too and it does all the work calculating the data to put into RAM, reading the RAM, and comparing the RAM to what it calculated it should be. And it's much more involved than that. Read the titles of the tests, now where do you think it's doing all that work? 256GB with an Atom CPU means long testing times.

What I can't tell is if memory interleaving is optimized without digging into a User Guide. Some systems RAM speeds slow down when you introduce interleaving. It doesn't sound right but I unfortunately have one of those, but I knew that when I purchased the setup and only have bank A filled. It is not a Supermicro system and I doubt this is a problem you are experiencing however I just wanted to not completely rule it out since this does exist out there.