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Independent memory mode installation order

Independent memory mode provides the highest level of memory performance, but lacks failover protection. The DIMM installation order for independent memory mode varies based on the number of processors and memory modules installed in the server.

Follow the rules below when installing memory modules in independent mode:
  • There should be at least one DDR5 DIMM per processor.
  • All DDR5 memory modules must operate at the same speed in the same system.
  • Memory population must be identical between processors.
  • Memory modules from different vendors are supported.
    Note
    When ThinkSystem 128GB TruDDR5 4800MHz (4Rx4) 3DS RDIMM v1 and/or ThinkSystem 256GB TruDDR5 4800MHz (8Rx4) 3DS RDIMM v1 is installed in a system, no other memory module types can be installed.
  • In each memory channel, populate the slot farthest from the processor (slot 0) first.
  • All memory modules must be DDR5 memory modules.
  • x8 memory modules and x4 memory modules cannot be mixed in a system.
  • Mixing 16Gbit (16 GB, 32 GB, 64 GB, 128 GB, 256 GB) and 24Gbit (96 GB) memory module is not allowed in a system.
  • 96 GB memory module must be identically populated in the system and only supported on Intel Xeon Platinum processor.
  • 96 GB memory module can only support 1DPC (8 DIMMs per processor) and 2DPC (16 DIMMs per processor) configurations.
  • All memory modules to be installed must be of the same type.
    • Value RDIMM cannot be mixed with non-value RDIMMs in a system.
    • 3DS RDIMM cannot be mixed with non-3DS RDIMMs in a system.
  • All memory modules in a system must have the same number of ranks.
  • When ThinkSystem 256GB TruDDR5 4800MHz (8Rx4) 3DS RDIMM v1 is installed in the system, the maximum number of supported drives is twenty-four drives.

With two processors

The following table shows the sequence of populating memory modules for independent mode when two processors are installed.

Table 1. Independent mode with two processors
Total DIMMsProcessor 1
16151413121110987654321
2 DIMMs10
4 DIMMs*      10      3  
8 DIMMs*141073
12 DIMMs*16 14   10  7 5 3  
16 DIMMs*161412107531
24 DIMMs*16 141312 10987 543 1
32 DIMMs*16151413121110987654321
Total DIMMsProcessor 2
32313029282726252423222120191817
2 DIMMs26
4 DIMMs*      26      19  
8 DIMMs*30262319
12 DIMMs*32 30   26  23 21 19  
16 DIMMs*3230282623211917
24 DIMMs*32 302928 26252423 212019 17
32 DIMMs*32313029282726252423222120191817
Note

DIMM configurations that support the Sub NUMA Clustering (SNC) feature, which can be enabled via UEFI. SNC is not supported if DIMM population does not follow the sequence indicated by the table above.

With three processors

The following table shows the sequence of populating memory modules for independent mode when three processors are installed.

Table 2. Independent mode with three processors
Total DIMMsProcessor 1
16151413121110987654321
3 DIMMs10
6 DIMMs*      10      3  
12 DIMMs*141073
18 DIMMs*16 14   10  7 5 3  
24 DIMMs*161412107531
36 DIMMs*16 141312 10987 543 1
48 DIMMs*16151413121110987654321
Total DIMMsProcessor 2
32313029282726252423222120191817
3 DIMMs26
6 DIMMs*      26      19  
12 DIMMs*30262319
18 DIMMs*32 30   26  23 21 19  
24 DIMMs*3230282623211917
36 DIMMs*32 302928 26252423 212019 17
48 DIMMs*32313029282726252423222120191817
Total DIMMsProcessor 3
33343536373839404142434445464748
3 DIMMs42
6 DIMMs*  35      42      
12 DIMMs*35394246
18 DIMMs*  35 37 39  42   46 48
24 DIMMs*3335373942444648
36 DIMMs*33 353637 39404142 444546 48
48 DIMMs*33343536373839404142434445464748
Note

DIMM configurations that support the Sub NUMA Clustering (SNC) feature, which can be enabled via UEFI. SNC is not supported if DIMM population does not follow the sequence indicated by the table above.

With four processors

The following table shows the sequence of populating memory modules for independent mode when four processors are installed.

Table 3. Independent mode with four processors
Total DIMMsProcessor 1
16151413121110987654321
4 DIMMs10
8 DIMMs*      10      3  
16 DIMMs*141073
24 DIMMs*16 14   10  7 5 3  
32 DIMMs*161412107531
48 DIMMs*16 141312 10987 543 1
64 DIMMs*16151413121110987654321
Total DIMMsProcessor 2
32313029282726252423222120191817
4 DIMMs26
8 DIMMs*      26      19  
16 DIMMs*30262319
24 DIMMs*32 30   26  23 21 19  
32 DIMMs*3230282623211917
48 DIMMs*32 302928 26252423 212019 17
64 DIMMs*32313029282726252423222120191817
Total DIMMsProcessor 3
33343536373839404142434445464748
4 DIMMs42
8 DIMMs*  35      42      
16 DIMMs*35394246
24 DIMMs*  35 37 39  42   46 48
32 DIMMs*3335373942444648
48 DIMMs*33 353637 39404142 444546 48
64 DIMMs*33343536373839404142434445464748
Total DIMMsProcessor 4
49505152535455565758596061626364
4 DIMMs58
8 DIMMs*  51      58      
16 DIMMs*51555862
24 DIMMs*  51 53 55  58   62 64
32 DIMMs*4951535558606264
48 DIMMs*49 515253 55565758 606162 64
64 DIMMs*49505152535455565758596061626364
Note

DIMM configurations that support the Sub NUMA Clustering (SNC) feature, which can be enabled via UEFI. SNC is not supported if DIMM population does not follow the sequence indicated by the table above.