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DDR5 RDIMMs mixed with CXL memory modules

This section contains information about how to install DDR5 RDIMMs mixed with CXL memory modules (CMMs) properly.

Supported CMM configurations​

The table below lists the CMM configurations supported by the server.
Table 1. Supported CMM configurations
DDR5 RDIMM per socketCMM per socket
DIMM quantityRDIMM modeCMM modeCMM capacity per moduleSupported CMM quantity
8 x 128 GB (2Rx4)Independent/mirroring1LM+Vol128 GB2/4/6
8 x 128 GB (2Rx4)IndependentHetero128 GB4
16 x 128 GB (2Rx4)Independent/mirroring1LM+Vol128 GB2/4/6
8 x 64 GB (2Rx4)Independent/mirroring1LM+Vol128 GB2/4/6
16 x 64 GB (2Rx4)
8 x 96 GB (2Rx4)Independent/mirroring1LM+Vol96 GB2/4/6
16 x 96 GB (2Rx4)
Note

  • Servers with Compute Complex Neptune Core Module do not support CMMs.

  • CMM modes:

    • 1LM+Vol: Native DDR5 (1LM) and (volatile) CMM are visible to software as two separate NUMA nodes.

    • Heterogeneous Interleave (Hetero): DDR5 and CMM are visible to software as one NUMA node, and they are interleaved together.
      Note
      The Hetero mode is not supported with LCC processors. For specific models of LCC processors, see the Processors section in SR650 V4 Product Guide.

  • To set the CMM mode, go to UEFI Setup > System Settings > Memory > CXL Memory Module > Memory Mode. For details, see CXL Memory Module.

CMM installation order​

For the CMM installation order, see: