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Oracle® Server X8-2 Service Manual

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Updated: January 2021

DIMM Population Rules

The population rules for adding DIMMs to the server are as follows:

  • The server supports 64-GB quad-rank (QR) Load-Reduced DIMMs (LRDIMMs), 32-GB dual-rank (DR) Registered DIMMs (RDIMMs), and 16-GB DR/SR RDIMMs.

  • Mixing 32-GB dual-rank DR 2Rx4 RDIMMs and 16-GB single-rank 1Rx4 SR RDIMMs in a server where the system is configured with a mix of both on every channel is supported.

  • Randomly mixing 32-GB dual-rank DR RDIMMs and 16-GB single-rank SR RDIMMs on channels can result in very low memory performance and is not supported.

  • Do not mix DIMM types in the server. For example, do not mix 64-GB LRDIMMs and 16-GB or 32-GB RDIMMs in the same server. If the server has 64-GB LRDIMMs installed, you cannot install 16-GB or 32-GB RDIMMs and vice versa.

  • If you are installing a mix of RDIMM sizes (for example, 16-GB and 32-GB), install the larger size RDIMMs first, then the smaller RDIMMs, until all of the RDIMMs are installed.

  • Each memory channel is composed of a black slot (channel slot 0) and a white slot (channel slot 1). Populate the black slot first, and then populate the white slot.

    Note -  The black slot for each channel must be populated first because it is considered furthest away from the processor.
  • The server supports either one DIMM per channel (1DPC) or two DIMMs per channel (2DPC).

  • The server operates properly with a minimum of one DIMM installed per processor.

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