Plugging rules for memory modules in the 9824-42A or 9856-42H system

Find information about the configurations and rules that apply to memory modules for the IBM Power S1124 (9824-42A) and IBM Power L1124 (9856-42H) system.

This information helps you to plan memory module installation in the system.

  • The system supports memory modules of 32 GB, 64 GB, 128 GB, or 256 GB.
  • A maximum of two memory module feature codes are supported on a system.
  • Equal quantities of the two memory module feature codes are not required except when mixing 128 GB and 256 GB memory modules under each system processor module.
  • The system supports two heights of memory: 2U and 4U. In the system, all the memory must be the same height.
The following tables list the feature codes of the supported memory modules.
Table 1. DDR5 memory sizes, types, feature codes, and heights for the 9824-42A system
Size Type Feature code Height
32 GB DDR5 EM54 2U
64 GB DDR5 EM5B 2U
128 GB DDR5 EM4M 4U
256 GB DDR5 EM5J 4U
Table 2. DDR5 memory sizes, types, feature codes, and heights for the 9856-42H system
Size Type Feature code Height
32 GB DDR5 EM59 2U
64 GB DDR5 EM5F 2U
DDR5 EM5L
128 GB DDR5 EM4G 4U
DDR5 EM4H
256 GB DDR5 EM5K 4U
DDR5 EM5N
The following figure shows the memory module locations.
Figure 1. Finding the memory module locations
Finding the memory module locations
For a two-processor system with a mixture of 128 GB and 256 GB memory modules under each system processor module (feature code EMCM), there must be an equal number of memory modules of each capacity under each system processor module and all the memory module slots must be populated. See Table 3 for memory module plugging rules for a two-processor system with a mixture of 128 GB and 256 GB memory modules under each system processor module.
Table 3. Memory module plugging rules for a two-processor system with a mixture of 128 GB and 256 GB memory modules under each system processor module (feature code EMCM)
Required number of memory modules Size Memory locations
16 256 GB P0-C21, P0-C27, P0-C32, P0-C40, P0-C16, P0-C35, P0-C43, P0-C48, P0-C12, P0-C13, P0-C19, P0-C20, P0-C17, P0-C18, P0-C25, P0-C26
16 128 GB P0-C28, P0-C29, P0-C38, P0-C39, P0-C36, P0-C37, P0-C46, P0-C47, P0-C30 P0-C31, P0-C41, P0-C42, P0-C33, P0-C34, P0-C44, P0-C45
If you do not have a two-processor system with a mixture of 128 GB and 256 GB memory modules under each system processor module, see the following tables for memory module plugging sequences and locations for your system.
Table 4. Plugging sequence for memory modules in a two-processor system with a single DDIMM Feature Code
Total memory modules Sequence Memory modules to install Memory locations
4 1 4 P0-C21, P0-C27, P0-C32, P0-C40
8 2 4 P0-C16, P0-C35, P0-C43, P0-C48
12 3 4 P0-C12, P0-C13, P0-C19, P0-C20
16 4 4 P0-C17, P0-C18, P0-C25, P0-C26
20 5 4 P0-C28, P0-C29, P0-C38, P0-C39
24 6 4 P0-C36, P0-C37, P0-C46, P0-C47
28 7 4 P0-C30 P0-C31, P0-C41, P0-C42
32 8 4 P0-C33, P0-C34, P0-C44, P0-C45
Note:
  • All memory module locations must be the same feature code.
Table 5. Plugging sequence for memory modules in a two-processor system with two DDIMM Feature Codes (FC A and FC B)
Total memory modules Sequence Memory modules to install Memory module feature code Memory locations
8 1 8 DDIMM FC A P0-C16, P0-C27, P0-C32, P0-C35
DDIMM FC B P0-C21, P0-C40, P0-C43, P0-C48
16 2 8 DDIMM FC A P0-C12, P0-C13, P0-C17, P0-C18
DDIMM FC B P0-C19, P0-C20, P0-C25, P0-C26
24 3 8 DDIMM FC A P0-C28, P0-C29, P0-C36, P0-C37
DDIMM FC B P0-C38, P0-C39, P0-C46, P0-C47
32 4 8 DDIMM FC A P0-C30, P0-C31, P0-C33, P0-C34
DDIMM FC B P0-C41, P0-C42, P0-C44, P0-C45
Note:
  • Maximum of two feature codes is supported.
  • Equal quantities of the two feature codes are not required.
  • All memory module locations for DDIMM FC A must be the same feature code.
  • All memory module locations for DDIMM FC B must be the same feature code.
  • The system does not support mixing DDR4 and DDR5 memory modules.
For a one-processor system with a mixture of 128 GB and 256 GB memory modules under the system processor module (feature code EMCM), there must be an equal number of memory modules of each capacity under the system processor module and all the memory module slots must be populated. See Table 6 for memory module plugging rules for a one-processor system with a mixture of 128 GB and 256 GB memory modules under the system processor module.
Table 6. Memory module plugging rules for a one-processor system with a mixture of 128 GB and 256 GB memory modules under the system processor module (feature code EMCM)
Required number of memory modules Size Memory locations
8 256 GB P0-C27, P0-C32, P0-C16, P0-C35, P0-C12, P0-C13, P0-C17, P0-C18
8 128 GB P0-C28, P0-C29, P0-C36, P0-C37, P0-C30, P0-C31, P0-C33, P0-C34
If you do not have a one-processor system with a mixture of 128 GB and 256 GB memory modules under the system processor module, see the following table for memory module plugging sequences and locations for your system.
Table 7. Plugging sequence for memory modules in a one-processor system with a single DDIMM Feature Code
Total memory modules Sequence Memory modules to install Memory locations
2 1 2 P0-C27, P0-C32
4 2 2 P0-C16, P0-C35
6 3 2 P0-C12, P0-C13
8 4 2 P0-C17, P0-C18
10 5 2 P0-C28, P0-C29
12 6 2 P0-C36, P0-C37
14 7 2 P0-C30 P0-C31
16 8 2 P0-C33, P0-C34
Note:
  • All memory module locations must be the same feature code.