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DRAM DIMM installation rules

For RDIMMs or LRDIMMs, the following memory modes are available:
Note

  • All DIMMs to be installed must be the same type. Do not mix RDIMM and LRDIMM in the same server.

  • When you install DIMMs with same rank and different capacity, install the DIMM that has the highest capacity first.

  • When you install DIMMs with different rank, install the DIMM with highest rank first.

  • Independent mode
    Independent mode provides high performance memory capability. You can populate all channels with no matching requirements. Individual channels can run at different DIMM timings, but all channels must run at the same interface frequency.
  • Mirroring mode
    In mirroring mode, each DIMM in a pair must be identical in size and architecture. The channels are grouped in pairs with each channel receiving the same data. One channel is used as a backup of the other, which provides redundancy.
  • Rank sparing mode
    In rank sparing mode, one rank of a DIMM works as the spare rank for the other ranks on the same channel. The spare rank is not available as system memory.