Mixing RAM capacities on R730XD

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TonyArrr

Active Member
Sep 22, 2021
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Straylia
Hi all,

First, I understand this is the "Processors and Motherboards" section that I'm posting a RAM question, but what I'm interested in based around the limitation of the Motherboard so I hope that's close enough to make that right :)

Been rocking a R730XD for about a year now, quite happy with it so far.
I've been wondering about my options for increasing RAM over time.

Currently I have 4x 32GB 2400mhz LRDIMMs. The user guide says:
Mixing of more than two memory module capacities in a system is not supported.
I'm wondering if this means the system will not boot if I added a pair of 64GB modules now, and a pair of 128GB modules later, while keeping the 32GB modules I already have, or if it just means that Dell would not provide troubleshoot support for a system configured that way.

Not that I know for sure I'd end up trying to do exactly that, I'm still good for memory capacity, but I'm expecting at the rate I'm going that I will benefit from upping the available RAM mid next year.
So if you can mix 3 different capacities, then that means I can just upgrade whenever it makes most sense for me, whereas if you really can only have 2 different module capacities installed, then no matter when I might want to upgrade, there would be incentive for me to hold off as long as possible to try and get 128GB modules at an affordable rate. Otherwise there runs the possibility a future RAM upgrade would also need to offset the loss of the 128GBs provided by the 32GB modules...

Thanks for taking the time to read, and hopefully someone who notices this will have the answer!
 

RolloZ170

Well-Known Member
Apr 24, 2016
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1,549
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first LRDIMM and RDIMM can not mixed.

you can not mix DIMM types within a channel, but 2x 32GB(2Rank) a channel A and 1x 64GB(4Rank) in channel B i.e.
if you don't populate all channels same size, unbalanced memory conf. result in bad bandwidth.
 
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