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Memory module installation rules and order

Memory modules must be installed in a specific order based on the memory configuration that you implement and memory modules installed in the server.

Supported memory types

For information on the types of memory module supported by this server, see Memory section in Technical Specifications.

Information about optimizing memory performance and configuring memory is available at the Lenovo Press website:

Memory - Lenovo Press

In addition, you can take advantage of a memory configurator, which is available at the following site:

Lenovo Enterprise Solutions Configurator (Memory Configurations)

Specific information about the required installation order of memory modules in your server based on the system configuration and memory mode that you are implementing is shown below.

Your server has 12 channels, 12 memory slots, and supports:
  • Capacity:
    • Minimum: 16 GB (1 x 16 GB RDIMM)
    • Maximum:

      • 3 TB (12 x 256 GB 3DS RDIMMs for 9004 series processors)

      • 1.5 TB (12 x 128 GB 3DS RDIMMs for 9005 series processors)

  • Memory module types for 9004 series processors:

    • TruDDR5 4800MHz x8 RDIMM: 16 GB (1Rx8), 32 GB (2Rx8), 48 GB (2Rx8)

    • TruDDR5 4800MHz 10x4 RDIMM: 32 GB (1Rx4), 64 GB (2Rx4), 96 GB (2Rx4)

    • TruDDR5 4800MHz 9x4 RDIMM: 32 GB (1Rx4), 64 GB (2Rx4)

    • TruDDR5 4800MHz 3DS RDIMM: 128 GB (4Rx4), 256 GB (8Rx4)

    • TruDDR5 5600MHz 10x4 RDIMM: 128 GB (2RX4)

  • Memory module types for 9005 series processors:

    • TruDDR5 6400 MHz x8 RDIMM: 16 GB (1Rx8), 32 GB (2Rx8), 48 GB (2Rx8)

    • TruDDR5 6400 MHz 10x4 RDIMM: 32 GB (1Rx4), 64 GB (2Rx4), 96 GB (2Rx4), 128 GB (2Rx4)

For a list of supported memory options, see Lenovo ServerProven website.

The following illustration helps you to locate the memory module slots on the system board (system board assembly).
Figure 1. Memory modules and processors layout
Memory module slots on the system board (system board assembly)

The memory-channel configuration table below shows the relationship between the processors, memory controllers, memory channels, and memory module slot numbers.

Table 1. Memory slot and channel identification
UMC No.21504391061178
Channel No.FEDCBAGHIJKL
DIMM No.121110987654321

Memory module installation guideline​

Follow the rules below when installing DIMMs:

DIMMsCoexist in a system
9x4 RDIMMs and other RDIMM typesx
3DS RDIMMs and other RDIMM typesx
128 GB 3DS RDIMMs and 256 GB 3DS RDIMMsx
x4 RDIMMs and x8 RDIMMsx
Different DRAM density (16Gbit, 24Gbit, and 32Gbit)1,2,5x (for 9004 series processors)
√ (for 9005 series processors)
RDIMMs of different capacity3,4√
1R RDIMMs and 2R RDIMMs4,5√
4R RDIMMs and 8R RDIMMs4x
RDIMMs manufactured by different vendors√
Note

  1. The 16Gbit DRAM is used in 16 GB, 32 GB, and 64 GB RDIMMs. The 24Gbit DRAM is used in 48 GB and 96 GB RDIMMs. The 32Gbit DRAM is used in 128 GB 2Rx4 RDIMMs.

  2. Before installing 24Gbit-based RDIMMs, make sure to apply the UEFI firmware version KAE108C or later to the server first and remove all existing 16Gbit-based RDIMMs.

  3. When installing RDIMMs of different capacity, install the RDIMM of the highest capacity first following the population sequence.

  4. For optimal performance, it is recommended to install RDIMMs of identical capacity and rank across all 12 channels.

  5. Mixing 1R and 2R RDIMMs or mixing RDIMMs based on different DRAM densities in a system equipped with 9005 series processors may have an impact on performance.

  6. Servers with 9004 series processors do not support 6400 MHz RDIMMs.

Memory module installation order​

Note
In the following tables:

  • S1-S12 indicate DIMM slots 1-12.

  • 1-12 indicate the installation order.

The following table shows the DIMM population sequence.

Table 2. DIMM population sequence
Total DIMMsSlot number
S12S11S10S9S8S7S6S5S4S3S2S1
1 DIMM1
2 DIMMs     12     
4 DIMMs3124
6 DIMMs   351264   
8 DIMMs73512648
10 DIMMs 79351264108 
12 DIMMs117935126410812