Subscribe to this information
POWER7 information
Memory riser placement and memory module balancing
Learn where to install memory risers and how to balance memory modules on the system.
Memory riser plugging sequence
Two configurations are available for the 8231-E2B, 8231-E1C, 8231-E1D, 8231-E2C, 8231-E2D, or 8268-E1D system.
When installing memory risers, follow this plugging sequence based
on the configuration.
| Number of system processors | Plugging Sequence |
|---|---|
| One system processor |
|
| Two system processors (to balance memory on each system processor) |
|
Figure 1. Memory riser plugging
sequence
Memory module balancing for the 8231-E2B
Plug the memory modules
into the slots shown in the following table and Figure 2.
Notes:
- The minimum memory that can be installed is 4 GB (two 2 GB DIMMs).
- Memory modules installed in the same processor module or memory card must be identical in size, speed, and feature code.
- Memory modules installed in different processor modules can be different sizes and speeds.
- Each memory feature consists of one pair of dual inline memory modules (DIMMs). Each memory card can have two or four DIMMs. Each processor module can have up to two memory cards and eight DIMMs. A memory feature is not required in all processor modules.
- When two processor modules are installed, alternate installing memory modules between the memory cards on the first processor module and the second processor module.
- After the second pair of memory modules, the memory modules must be installed as a quad.
| Processors and memory | Where to install memory modules |
|---|---|
| One processor module, one memory card (memory plugged in pairs) |
Notes:
|
| One processor module, two memory cards (plugged in quads) |
Notes:
|
| Two processor modules (plugged in quads) | Balance memory on each processor card unless
you have an odd number of memory modules. When possible, balance memory
modules on each processor module in the following order:
Notes:
|
Memory module balancing for the 8231-E1C, 8231-E1D, 8231-E2C, 8231-E2D, or 8268-E1D
Plug the memory
modules into the slots shown in the following table and Figure 2.
Notes:
- One memory card is supported in either a one-processor module configuration or a two-processor module configuration.
- Each memory card is independent of other memory cards installed in the system. DIMMs installed on each memory card can be different from DIMMs on other memory cards.
- At least one pair of DIMMs must be installed on each memory card. The first pair of DIMMs on each memory card can be any size. An additional pair of DIMMs can be installed on each memory card.
- On each memory card, the pair of DIMMs installed at slots C1 and C2 must be identical. The pair of DIMMs installed at slots C3 and C4 must be identical. However, one pair of DIMMs can be different from another.
- When any DIMM fails, the other DIMM within the pair will be unconfigured.
- Optional: For the best performance, use identical DIMM configurations on the memory cards.
| Processors and memory | Where to install memory modules |
|---|---|
| One processor module, one memory card (memory plugged in pairs) |
Note: The memory module sizes can be 2 GB, 4 GB, 8 GB, or 16
GB.
|
| One processor module, two memory cards (memory plugged in pairs) |
|
| Two processor modules, two memory cards (memory plugged in pairs) |
|
| Two processor modules, three memory cards (memory plugged in pairs) |
|
| Two processor modules, four memory cards (memory plugged in pairs) |
|
Figure 2. Memory module slot
locations
