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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.

For a list of supported memory options, see Lenovo ServerProven website.

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.

Note
MRDIMMs are supported only on servers equipped with processor 6747P, 6761P, 6767P, 6781P, or 6787P.

Memory modules and processors layout​

The following illustration helps you to locate the memory module slots on the processor board. The memory-channel identification table below shows the relationship between the processors, memory controllers, memory channels, and memory module slot numbers.
Figure 1. Memory module slots on the processor board
Memory module slots on the system board

Table 1. Memory slot and channel identification
ProcessorCPU 1
ControlleriMC7iMC6iMC5iMC4iMC0iMC1iMC2iMC3
ChannelCH7CH6CH5CH4CH0CH1CH2CH3
Slot No.0101010110101010
DIMM No.16151413121110987654321
ProcessorCPU 2
ControlleriMC7iMC6iMC5iMC4iMC0iMC1iMC2iMC3
ChannelCH7CH6CH5CH4CH0CH1CH2CH3
Slot No.0101010110101010
DIMM No.32313029282726252423222120191817

  • Slot No.: DIMM slot number in each memory channel. Each memory channel has two DIMM slots: slot 0 (further from the processor) and slot 1 (closer to the processor).

  • DIMM No.: DIMM slot number on the processor board. Each processor has 16 DIMM slots.

Memory module installation guideline​

  • At least one DIMM is required for each processor. Install at least eight DIMMs per processor for good performance.

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

  • For memory module installation rules and orders, see:
  • Independent mode installation order
    In independent mode, memory channels can be populated with DIMMs in any order and you can populate all channels for each processor in any order with no matching requirements. Independent mode provides the highest level of memory performance, but lacks failover protection. The DIMM installation order for independent mode varies based on the number of processors and memory modules installed in the server.
  • Mirroring mode installation order
    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. The DIMM installation order for memory mirroring varies based on the number of processors and DIMMs installed in the server.