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Memory configuration

Memory performance depends on several variables, such as memory mode, memory speed, memory ranks, memory population and processor.

More information about optimizing memory performance and configuring memory is available at the Lenovo Press website:

Memory - Lenovo Press

In addition, you can take advantage of a memory configurator tool, which is available at the following site:

Lenovo Enterprise Solutions Configurator

For specific information about the required installation order of memory modules in your server based on the system configuration and memory mode that you are implementing, see Memory module installation rules and order.

  • Independent memory mode
    Independent memory mode provides the highest level of memory performance, but lacks failover protection.
  • Memory mirroring
    Memory-mirroring mode provides full memory redundancy while reducing the total system memory capacity in half. Memory channels are grouped in pairs with each channel receiving the same data. If a failure occurs, the memory controller switches from the DIMMs on the primary channel to the DIMMs on the backup channel.
  • Memory sparing
    In memory-sparing mode, one memory rank serves as a spare for other ranks on the same channel in case they fail. The spare rank is held in reserve and not used as active memory until a failure is indicated, with reserved capacity subtracted from the total available memory in the system. After an error threshold is surpassed in a system protected by memory sparing, the content of a failing rank of DIMMs is copied to the spare rank. The failing rank is then taken offline and the spare rank placed online for use as active memory in place of the failed rank. Since the failover process involves copying of memory content, the level of memory redundancy provided by memory sparing is less than that provided by memory mirroring: memory mirroring is the preferred failure-protection choice for critical applications.
  • Configure DC Persistent Memory Module (DCPMM)
    Follow the instructions in this section to configure DCPMMs and DRAM DIMMs.