IBM x3500 - System - 7977 Installation Manual page 26

v Installing additional DIMMs in both memory branches will improve system
v The server supports memory mirroring (mirroring mode) and online-spare
12
IBM System x3500 Type 7977: Installation Guide
Branch 0
Channel 1
Channel 0
DIMM 3
DIMM 6
DIMM 2
DIMM 5
DIMM 4 DIMM 1
performance.
memory.
– Memory mirroring replicates and stores data on DIMMs within two branches
simultaneously. You must enable memory mirroring through the
Configuration/Setup Utility program (for more information, see the section
about configuring the server in the User's Guide on the IBM System x
Documentation CD). To enable memory mirroring in the Configuration/Setup
Utility program, select Devices and I/O Ports → Advanced Chipset Control →
Memory Branch Mode. Use the arrow keys to change the Memory Branch
Mode setting to Mirror; then, save your changes. When you use memory
mirroring, consider the following information:
- The maximum available memory is reduced to 16 GB; 32 GB is available in
non-mirroring mode.
- The minimum memory configuration is four identical DIMMs. You must
install identical pairs of fully buffered, dual inline memory modules (DIMMs)
in all four DIMM connectors (same size, type, speed, and technology).
These DIMMs must span both branches and all four channels. For
example, when you install the first four DIMMs, you must install two DIMMs
in branch 0 (one in channel 0 and one in channel 1) and two DIMMs in
branch 1 (one in channel 2 and one in channel 3). See Table 2 for the
DIMM installation sequence.
- When you upgrade the server to eight DIMMs, the DIMMs that are next to
each other (for example, DIMM connector 1 and DIMM connector 4) within
the channels of a branch must be identical in size, type, speed, and
technology. However, the DIMMs in the connectors above and below each
other within the channels of a branch do not have to be identical to each
other (for example, the DIMMs in DIMM connector 1 and DIMM connector
2).
- Both branches operate in dual-channel mode.
The following table shows the DIMM configuration upgrade sequence for
mirroring mode.
Table 2. DIMM upgrade configuration sequence in mirroring mode
Number of DIMMs
4
8
12
Branch 1
DIMM 9
DIMM 12
DIMM 11 DIMM 8
DIMM 10 DIMM 7
DIMM connectors
1, 4, 7, 10
1, 4, 7, 10, 2, 5, 8, 11
1, 4, 7, 10, 2, 5, 8, 11, 3, 6, 9, 12
Channel 3
Channel 2