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Independent mode installation order

In independent mode, memory channels can be populated with DIMMs in any order and you can populate all channels for each processor in any order with no matching requirements. Independent mode provides the highest level of memory performance, but lacks failover protection. The DIMM installation order for independent mode varies based on the number of processors and memory modules installed in the server.

Independent mode installation rules​

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.

  • In each memory channel, populate the slot farthest from the processor (slot 0) first.

  • All DIMMs must be all DDR5 DIMMs.

  • x8 DIMMs and x4 DIMMs cannot be mixed in a system.

  • All memory modules to be installed must be of the same type.

    • 9x4 RDIMM cannot be mixed with non-9x4 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, except for below conditions:

    • Single-rank RDIMMs can be mixed with dual-rank RDIMMs when there are 16 DIMMs populated for each processor.

    • Quad-rank 3DS RDIMMs can be mixed with octal-rank 3DS RDIMMs when there are 16 DIMMs populated for each processor.

      Note
      System hang on POST may occur on a server operating in this configuration. In this case, contact Lenovo service to replace the failed DIMM for proper operation.
    • See Independent mode with mixing rank for more information on the installation sequence when installing memory modules with different ranks.
  • Different DRAM density (16Gbit, 24Gbit, and 32Gbit) cannot be mixed in a system.
    Note
    The 16Gbit DRAM is used in 16 GB, 32 GB, and 64 GB RDIMMs. The 24Gbit DRAM is used in 24 GB, 48 GB, and 96 GB RDIMMs. The 32Gbit DRAM is used in 128 GB 2Rx4 RDIMMs.

  • The 4800 MHz 48 GB and 96 GB RDIMMs are supported only on servers with SPR XCC or MCC processors.

  • The 5600 MHz 128 GB 2Rx4 RDIMM is supported only on servers with XCC or MCC processors.

  • Before installing 24Gbit-based RDIMMs in a system with SPR XCC or MCC processors, make sure to apply the UEFI firmware version ESE126H or later to the server first.

  • Before installing 32Gbit-based RDIMMs in a system with XCC or MCC processors, make sure to apply the UEFI firmware version ESE128E or later to the server first.

For optimal performance, you are recommended to install DIMMs in Standard DIMM installation order. The Optional DIMM installation order is used only for special requirements.

Standard DIMM installation order​

The following tables show the standard orders of populating memory modules for independent mode.

Table 1. Independent mode with one processor
Total DIMMsProcessor 1
16151413121110987654321
1 DIMM17
2 DIMMs2  14      7      
4 DIMMs2141073
6 DIMMs1,2  14 12 10  7   3 1
8 DIMMs1,2,3,4,5161412107531
12 DIMMs2,616 141312 10987 543 1
16 DIMMs2,3,4,6,7,816151413121110987654321
Note

  1. The DIMM configurations support 5600 MHz 24 GB, 48 GB, and 96 GB RDIMMs.

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

  3. The DIMM configurations support Software Guard Extensions (SGX). See Enable Software Guard Extensions (SGX) to enable this feature.

  4. The DIMM configurations support 4800 MHz 96 GB RDIMMs.

  5. The DIMM configurations support 4800 MHz 48 GB RDIMMs.

  6. The DIMM configurations support 5600 MHz 96 GB RDIMMs.

  7. Rank mixing is supported between single-rank and dual-rank RDIMMs, or between quad-rank and octal-rank 3DS RDIMMs when there are 16 DIMMs populated for each processor. See Independent mode with mixing rank for more information on the installation sequence when installing memory modules with different ranks.

  8. Mixing of DDR5 4800 MHz 128 GB and 256 GB 3DS RDIMMs is supported when there are 16 DIMMs populated for each processor.

Table 2. Independent mode with two processors
Total DIMMsProcessor 1
16151413121110987654321
2 DIMMs17
4 DIMMs2  14      7      
8 DIMMs2141073
12 DIMMs1,2  14 12 10  7   3 1
16 DIMMs1,2,3,4,5161412107531
24 DIMMs2,616 141312 10987 543 1
32 DIMMs2,3,4,6,7,816151413121110987654321
Total DIMMsProcessor 2
32313029282726252423222120191817
2 DIMMs123
4 DIMMs2  30      23      
8 DIMMs230262319
12 DIMMs1,2  30 28 26  23   19 17
16 DIMMs1,2,3,4,53230282623211917
24 DIMMs2,632 302928 26252423 212019 17
32 DIMMs2,3,4,6,7,832313029282726252423222120191817
Note

  1. The DIMM configurations support 5600 MHz 24 GB, 48 GB, and 96 GB RDIMMs.

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

  3. The DIMM configurations support Software Guard Extensions (SGX). See Enable Software Guard Extensions (SGX) to enable this feature.

  4. The DIMM configurations support 4800 MHz 96 GB RDIMMs.

  5. The DIMM configurations support 4800 MHz 48 GB RDIMMs.

  6. The DIMM configurations support 5600 MHz 96 GB RDIMMs.

  7. Rank mixing is supported between single-rank and dual-rank RDIMMs, or between quad-rank and octal-rank 3DS RDIMMs when there are 16 DIMMs populated for each processor. See Independent mode with mixing rank for more information on the installation sequence when installing memory modules with different ranks.

  8. Mixing of DDR5 4800 MHz 128 GB and 256 GB 3DS RDIMMs is supported when there are 16 DIMMs populated for each processor.

Optional DIMM installation order​

The following table shows the optional orders of populating memory modules for independent mode.

Table 3. Optional installation order
ProcessorTotal DIMMsOptional installation order
Processor 11 DIMM

  • Slot 12

  • Slot 10

  • Slot 5

2 DIMMs1,2

  • Slots 10, 3

6 DIMMs1

  • Slots 16, 14, 10, 7, 5, 3

  • Slots 16, 12, 10, 5, 3, 1

  • Slots 16, 14, 12, 7, 5, 1

12 DIMMs1,3

  • Slots 16, 15, 14, 12, 11, 10, 7, 6, 5, 3, 2, 1

Processors 1 and 22 DIMMs

  • Slots 26, 10

  • Slots 21, 5

  • Slots 28, 12

4 DIMMs1,2

  • Slots 26, 19, 10, 3

12 DIMMs1

  • Slots 32, 30, 26, 23, 21, 19, 16, 14, 10, 7, 5, 3

  • Slots 32, 28, 26, 21, 19, 17, 16, 12, 10, 5, 3, 1

  • Slots 32, 30, 28, 23, 21, 17, 16, 14, 12, 7, 5, 1

24 DIMMs1,3

  • Slots 32, 31, 30, 28, 27, 26, 23, 22, 21, 19, 18, 17, 16, 15, 14, 12, 11, 10, 7, 6, 5, 3, 2, 1

Note

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

  2. The DIMM configuration does not support 5600 MHz 24 GB, 48 GB, and 96 GB RDIMMs.

  3. The DIMM configuration does not support 5600 MHz 24 GB and 48 GB RDIMMs.

  • Independent mode with mixing rank
    Follow the memory module installation sequence in this section when installing memory modules with different ranks in independent mode.