Dell R900 manual Non-Optimal Memory Configurations, Memory Sparing Support

•Mirrored mode requires the same DIMM type across and up-and-down channels.

•In Single Channel Mode, a DIMM must be populated in the Branch 0, Channel A, DIMM 1 slot first, then you can populate the Channel A up to all 8 DIMMs.

•For the Dual Channel Mode, the memory capacity upgrade path would be to populate Branch 0 of Channel A and Channel B with the same DIMM number and type, or Branch 1 of Channel C and Channel D with the same DIMM number and type.

Non-Optimal Memory Configurations

System performance can be affected if your memory configuration does not conform to the preceding installation guidelines. Your system may issue an error message during startup stating that your memory configuration is non- optimal.

The server will support a population of DIMMs with different speed ratings. The overall system memory speed will be determined by the slowest DIMM populated.

The server will support population of mixed memory suppliers, provided all other rules above are followed.

Memory Sparing Support

The system supports memory sparing if eight identical memory modules are installed in the system. The memory sparing feature must be enabled in the System Setup program and can be used only if memory mirroring is not enabled.

Memory sparing allocates four ranks of DIMM memory to the spare bank. These four ranks consist of the first rank of memory in DIMM sockets 1 through 4. For single-rank DIMMs, the entire capacity of the four DIMMs is allocated to sparing whereas for dual-rank DIMMs, only half of the four- DIMM capacity is allocated to sparing. Table 3-1shows how memory sparing splits the available and spared memory in each of the single- and dual-ranked memory module combinations.

Installing System Components

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