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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 each processor in any order with no matching requirements. Independent memory mode provides the highest level of memory performance, but lacks failover protection. The DIMM installation order for independent memory mode varies based on the number of processors and memory modules installed in the node.

Memory module installation order in independent mode

Follow the rules below when installing memory modules in independent mode:
  • All memory modules must be DDR5 memory modules.
  • At least one DDR5 DIMM is required per installed processor.
  • All DDR5 DIMM must operate at the same speed in the same node.
  • Memory population must be identical between processors.
  • Memory modules from different vendors are supported.
  • In each memory channel, populate the slot farthest from the processor (slot 0) first.
  • Mixing x8 and x4 DIMM is not supported in a node.
  • All the installed memory modules must be of the same type.
Note
System hang on POST may occur on a server operating in this configuration. In this case, contact Lenovo service to replace the failed DIMM for proper operation.

With one processor

The following table shows the DIMM population sequence for independent memory mode when one processor is installed.

Table 1. Independent mode memory population sequence for one processor
Total DIMMsProcessor 1
87654321
14
2 * 7  4   
4*7542
6 7654 21
887654321
Note

* When there are two or four DIMMs installed per processor, 24 GB or 48 GB DIMMs are not supported.

With two processors

The following tables show the DIMM population sequence for independent memory mode when two processors are installed.

Table 2. Independent mode memory population sequence for two processors
Total DIMMsProcessor 1
87654321
2 4
4* 7  4   
8*7542
12 7654 21
1687654321
Total DIMMsProcessor 2
910111213141516
2 13
4* 10  13   
8*10121315
12 10111213 1516
16910111213141516
Note

* When there are two or four DIMMs installed per processor, 24 GB or 48 GB DIMMs are not supported.