RAM Selection

Hello Guys,

I’m going to purchase RAM for my Supermicro Motherboard. Its X12SPM-LN6TF from Supermicro. However, I’m not sure whether i should go for RDIMM or LRDIMM. Any advice would be very helpful.


Basically a speed vs. capacity question.
Depends on your needs.

Do you need more than 32GB(?) per module?
Then go with LR.
Otherwise R Dimms are cheaper and available in higher clocks/lower latency.


Yes, planning to use 64GB per DIMM.

You mean RDIMM have higher clock and lower latency?

“You mean RDIMM have higher clock and lower latency?”
But double or even quadruple the capacity is nearly always better than the advantage of slightly higher clocks.

Hmm. What about latency?

I’m going to get MTA36ASF8G72LZ-2G9B1 (Micron). Is that a good option? Getting it via local seller.

Any thoughts @etorix @ericloewe ?

Any compatible ECC module from Micron, Samsung or SK Hynix should be a good option.


Yes, that’s the basic thing i understand. But I’m clueless about whether i should go for RDIMM or LRDIMM ;(

RDIMM is more performant and generally cheaper than a Load Reduced DIMM.

The load is reduced with additional electronics and delays :wink:

The LRDIMMs are used when you need them for capacity reasons.

1 Like

Hmm. What kind of load are we talking about here specifically? And with those, does it adds more delays to the processing?

Also, i heard about RDIMM (3DS), how different it is from 3DS?

…and since that motherboard lists the same max RAM capacity for RDIMMs and LRDIMMs, there’s literally no reason to use LRDIMMs.


Memory controller load.
3DS is yet another subtype with higher capacity than standard RDIMM.

Check the motherboard’s compatibility and then pick whatever suits you/is available. Do not overthink it.


I came to the same conclusion. Thanks, Dan!

Got it. Going with RDIMM!

Thank you guys for all the help!

@etorix @ericloewe Can you guys confirm if this is the right one?


I’m not sure whether its RDIMM or LRDIMM ;(

DuckDuckGo sent me to this page, which clearly indicates RDIMM. I’m surprised that this is DDR4-2933, intended for a board which can do 3200, but maybe your CPU is limited to 2933 anyway. (Intel SKU List: Hello dear customer. How can I confuse you today?)
And, again, 2933 vs. 3200 or RDIMM vs. LRDIMM matters less to ZFS than capacity.

Mine is 2G9B1TI and the one you got in search result is 2GNR. Some site says its RDIMM and some says LRDIMM. I’m confused ;(

Man, don’t ask. Their support is pathetic, not sure if their representative are super noobs or act like noobs to avoid the questions in the first place. They’re not aware of their own product they manufacture and on other hand, there is Chelsio. Just WOW.


Fair point. i re-ran the search with double quotes, with and without the final TI and all results I got are still 64 GB DDR4-2933 RDIMM modules. Here, there, with datasheet :tada: or from Supermicro.
Still no confusion… but the prices seem quite high.