IBM x3690 X5 Service Manual page 317

Table 19. non--mirroring mode (normal) DIMM population sequence when one or two
microprocessors and no memory tray is installed (continued)
Pairs of DIMMs
Pair 2
Pair 3
Pair 4
Pair 5
Pair 6
Pair 7
Pair 8
– The following table lists the DIMM installation sequence for non-mirroring
mode when two microprocessors and a memory tray is installed in the server:
Table 20. Non-mirroring mode (normal) DIMM population sequence when two
microprocessors and a memory tray is installed
Pairs of DIMMs
Pair 1
Pair 2
Pair 3
Pair 4
Pair 5
Pair 6
Pair 7
Pair 8
v Memory-mirroring mode: When you use the memory mirroring feature,
consider the following information:
– Memory-mirroring mode replicates and stores data on sets of four DIMMs
simultaneously. If a failure occurs, the memory controller switches from the
set of memory DIMMs to the backup set of DIMMs. To enable memory
mirroring through the Setup utility, select System Settings → Memory. For
more information, see "Using the Setup utility" on page 402.
– DIMMs must be installed in sets of four. The DIMMs in each set must be the
same size and type. This is applicable also when you have the optional
memory tray installed in the server and the optional IBM MAX5 for System x
attached to the server. You must install DIMMs in sets of four DIMMs for
memory-mirroring mode in each one (the server, memory tray, and the
MAX5).
– The maximum available memory is reduced to half of the installed memory
when memory mirroring is enabled. For example, if you install 64 GB of
memory, only 32 GB of addressable memory is available when you use
memory mirroring.
Number of installed
microprocessors
1 or 2
1 or 2
1 or 2
1 or 2
1 or 2
1 or 2
1 or 2
DIMM connector
Number of population
installed sequence on the
microprocessors system board
2 1, 8
2 9, 16
2 3, 6
2 11, 14
2 2, 7
2 10, 15
2 4, 5
2 12, 13
Chapter 5. Removing and replacing components
DIMM connector
population sequence with
no memory tray
9, 16
3, 6
11, 14
2, 7
10, 15
4, 5
12, 13
DIMM connector
population sequence
on the memory tray
17, 24
25, 32
19, 22
27, 30
18, 23
26, 31
20, 21
28, 29
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