Unbuffered DIMMs (UDIMMs)

The following tips provide information that you must consider when you install UDIMMs.
  • The memory channels run at the lowest common frequency of the DIMMs installed.
  • The UDIMM options that are available for the server are 4 GB, 8 GB, and 16 GB DIMMs.
  • The server supports up to two single-rank or dual-rank UDIMMs per channel.

  • It is recommended to install DIMMs with the same rank in each channel.

  • The following table lists the supported UDIMM population.
    Table 1. Supported UDIMM population per channel.

    Five-column table for documenting the DIMM slots per channel, DIMMs installed in each channel, DIMM type, DIMM speed, and ranks per DIMM (any combination).
    DIMM slots per channel DIMMs installed in each channel DIMM type DIMM speed Ranks per DIMM (any combination)
    2 1 Unbuffered DDR4 ECC 2133/2400 Dual-rank
    2 2 Unbuffered DDR4 ECC 2133/2400 Dual-rank
  • The following table lists the maximum DIMM population using ranked UDIMMs.
    Table 2. Maximum memory population using ranked UDIMMs (depending on your model).

    Four-column table for documenting the number of UDIMMs, DIMM type, size, and total memory.
    Number of UDIMMs DIMM type Size Total memory
    4 Dual-rank UDIMMs 16 GB 64 GB
  • The following table shows the UDIMM memory installation sequence to optimize the system performance.
    Table 3. DIMM installation sequence.

    Two-column table for documenting the number of DIMMs and installation sequence (connectors).
    Number of DIMMs Installation sequence (DIMM slots)
    First pair of DIMMs 3, 1
    Second pair of DIMMs 4, 2

Parent topic: DIMM installation guidelines