ram comparability question for server - looking for single sticks of 64GB ddr3

iliak

Member
Oct 2, 2018
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i am planing to expand our servers ram, i have the following and i would like to know what model it is compatible

  • server (dell m620 ) with 16 *16GB HMT42GR7BMR4C-G7 - SK Hynix 16GB DDR3-1066 RDIMM PC3-8500R Quad Rank x4 Module
    • i would like to add 4 more sticks of 64 GB what more are compatible ?
  • server(dell m620) with 16*16Gb M393B2G70QH0-YK0 - Samsung 16GB DDR3-1600 RDIMM PC3L-12800R Dual Rank x4 Module
    • i would like to add 4 more sticks of 64 GB what more are compatible ?
  • server (m820) with 32*16GB M393B2G70BH0-YH9 - Samsung 16GB DDR3-1333 RDIMM PC3L-10600R Dual Rank x4 Module
    • i would like to add 8 more sticks of 64GB each


if i can buy a single type to be compatible for all for example a 64 GB stick it would be better because we have multiple servers for each, and for larger quantity ill get a better price\unit,
 
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NablaSquaredG

Active Member
Aug 17, 2020
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  • server (dell m620 ) with 16 *16GB HMT42GR7BMR4C-G7 - SK Hynix 16GB DDR3-1066 RDIMM PC3-8500R Quad Rank x4 Module
    • i would like to add 4 more sticks of 64 GB what more are compatible ?
  • server(dell m620) with 16*16Gb M393B2G70QH0-YK0 - Samsung16GB DDR3-1600 RDIMM PC3L-12800R Dual Rank x4 Module
    • i would like to add 4 more sticks of 64 GB what more are compatible ?
  • server (m820) with 32*16GB M393B2G70BH0-YH9 - Samsung 16GB DDR3-1333 RDIMM PC3L-10600R Dual Rank x4 Module
    • i would like to add 8 more sticks of 64GB each
No, you can't. Mixing different DIMMs sizes is already a disaster, but mixing RDIMMs and LRDIMMs does not work ("RDIMMs and LRDIMMs must not be mixed", p55 of M820 manual)

RAM compat table for M620:
1610618461134.png

You are also going to need Xeon v2 CPUs in order to be able to use Octal-Rank 64GB LRDIMMs at all:
1610618605039.png

(Sorry it's in German. Zweifach = Dual, Achtfach = Octal).

Very similar for the M820 (Manual in English here: https://dl.dell.com/topicspdf/poweredge-m820_owners-manual_en-us.pdf , page 54)
 

iliak

Member
Oct 2, 2018
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The cpu on 820 is CPU E5-4657Lv2, and on 620 E5-2695 v2
what is the largest stick i can put in it ? 32rdim?

does 32GB stick rdim, 1600 will work with all of them ?
 
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NablaSquaredG

Active Member
Aug 17, 2020
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You CAN put in 64GB Octal Rank LRDIMMs, but you cannot mix them with the existing RDIMMs.

Just look at the table. M620 (for Xeon v2 CPUs):
1 LRDIMM per Channel (8 in total => 512GB) : 1600MHz
2 LRDIMMs per Channel (16 in total => 1024GB): 1600MHz
3 LRDIMMs per Channel (24 in total => 1536GB): 1066MHz

M820:
1 LRDIMM per Channel (8 in total => 512GB) : 1600MHz
2 LRDIMMs per Channel (16 in total => 1024GB): 1333MHz
3 LRDIMMs per Channel (24 in total => 1536GB): 1066MHz

(funny that according to the datasheet the M620 supports higher speed with 2 LRDIMMs per Channel than the M820. Could as well be a typo in the manual though)

Re compatible memory: 64GB LRDIMMs are very expensive and Dell does not publish memory QVL, as they only want to sell their own memory. You should make sure that you can get a refund if the DIMMs don't work. But it's very unlikely that LRDIMMs wouldn't work, so don't worry too much.
 

iliak

Member
Oct 2, 2018
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we dont have a budget to replace all the ram, (future servers will be based on LRDIM to support more memory scalability ),
this time we will just fill some empty slots with more sticks
 

iliak

Member
Oct 2, 2018
64
20
8
Re compatible memory: 64GB LRDIMMs are very expensive and Dell does not publish memory QVL, as they only want to sell their own memory. You should make sure that you can get a refund if the DIMMs don't work. But it's very unlikely that LRDIMMs wouldn't work, so don't worry too much.
the speed is not the issue, our bottleneck will be the cpu

Like I said, you can't mix RDIMMs with LRDIMMs, it won't work.
what about HMT84GR7DMR4C-PB - SK Hynix 1x 32GB DDR3-1600 RDIMM PC3-12800R Quad Rank x4 Module
 
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