1. Exadata Server X11M Service Manual
  2. Servicing DIMMs
  3. DIMM Population Rules

DIMM Population Rules

The population rules for adding DIMMs to Exadata Server X11M are as follows:

  • The server supports:

    • Up to 24 DDR5 DIMMs, 12 per processor socket.

    • 32 GB, 64 GB, 96 GB, and 128 GB dual-rank (DR) Registered DIMMs (RDIMMS).

    • Up to 3 TB memory when populating the 24 DIMM slots with 128-GB DIMMs.

    • 1 DIMM per channel (1DPC). Each DIMM channel is composed of a black slot.

    • A maximum supported memory speed of 4800 MT/s.

      However, the maximum attainable memory speed could be limited by the maximum speed supported by a specific processor or DIMM. All memory installed in the system operates at the same speed, or frequency.

  • Populate all 12 memory DIMMs per processor to achive the highest system performance. If populating 12 memory DIMMs per processor is not feasible, populate each processor with 1, 2, 4, 6, 8, or 10 DIMMs.

  • Populate each memory channel with the same capacity and number of banks.

  • Populate processor 0 (P0) and processor 1 (P1) using the same DIMM configuration. Failure to do so will result in lower system performance.

  • The server operates properly with a minimum of one DIMM installed per processor. Install one DIMM in slot D5 on each processor.

  • Each DIMM is shipped with a label identifying its rank classification (dual or quad). The following identifies the label corresponding to the supported DIMM rank classification: Dual-rank RDIMM 2Rx4

  • Do not mix DIMM sizes in a server even if they are the same type. For example, you cannot mix 96 GB RDIMMs with 64 GB RDIMMs on the same server.

  • Do not mix DIMM types in a server. Load-Reduced (LRDIMMs) are not supported.

  • Do not mix DIMM module types within a memory channel. All DIMM module types must be RDIMM module types, with the same ECC configuration.

  • Do not mix x4 and x8 DIMMs within a memory channel.

  • The server does not support lockstep memory mode, which is also known as double device data correction, or Extended ECC.

  • Populate the DIMM slots in the order described in the following sections, which provide an example of how to populate the DIMM slots to achieve optimal system performance.