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Memory module installation rules and order

Memory modules must be installed in a specific order based on the memory configuration that you implement and the number of processors and memory modules installed in the server.

Supported memory types

For information on the types of memory module supported by this server, see Memory section in Technical Specifications.

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, which is available at the following site:

Lenovo Enterprise Solutions Configurator (Memory Configurations)

For the specific information about the required installation order of memory modules in SD520 V4 based on the system configuration and memory mode that you are implementing, see below.

Memory modules and processors layout​

Figure 1. Memory modules and processors layout
Memory module and processor location

The memory-channel configuration table below shows the relationship between the processors, memory controllers, memory channels, and memory module slot numbers.

Table 1. Memory slot and channel identification
ChannelCH 7/HCH 6/GCH 5/FCH 4/EProcessorCH 0/ACH 1/BCH 2/CCH 3/D
DIMM slot No.12345678

Memory module installation guideline​

  • Install eight DIMMs for good performance.

  • When a DIMM is replaced, the node provides automatic DIMM enablement capability without requiring you to use the Setup Utility to enable the new DIMM manually.

Attention
  • Install DIMMs of the same speed for optimal performance. Otherwise, the BIOS will find and run the lowest speed among all channels.
  • Within a channel, always populate DIMMs with the maximum number of ranks in the farthest DIMM slot, followed by the nearest DIMM slot.
  • Independent memory mode installation order
    In independent memory mode, memory channels can be populated with DIMMs in any order and you can populate all channels for the processor in any order with no matching requirements. Independent memory mode provides the highest level of memory performance, but lacks failover protection.
  • Memory mirroring mode installation order
    Memory-mirroring mode provides full memory redundancy while reducing the total node 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.