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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)

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 is shown 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
ProcessorProcessor 2 Processor 1
Channel numberLKJIHGABCDEFLKJIHGABCDEF
DIMM slot number242322212019181716151413121110987654321

Independent memory mode installation order​

Independent memory mode guidelines:
  • Populate identical memory capacity and rank per memory channel and processor.
  • Dual Socket (2P) socket interleaving (NPS0, dual socket system as one NUMA node) can be supported only if:
    1. There is an equal number of populated memory channels per socket and equal number of channels populated in each side of both sockets.
    2. All populated memory channels across both sockets are populated with symmetric memory capacity.
Note
SR685a V3 supports fully populated processors only.