Memory Rank Sparing - Lenovo x3550 M5 Installation And Service Manual

• The maximum available memory is reduced to half of the installed memory when memory mirrored
channel is enabled. For example, if you install 64 GB of memory using RDIMMs, only 32 GB of
addressable memory is available when you use memory mirrored channel.
The following diagram lists the DIMM connectors on each memory channel.
Microprocessor 2
Figure 84. Connectors on each memory channel
The following table shows the installation sequence for memory mirrored channel mode:
Table 28. Memory mirrored channel mode DIMM population sequence
DIMMs
One Microprocessor
1st set
2nd set
3rd set
4th set
5th set
6th set
Two Microprocessors
1st set
2nd set
3rd set
4th set
5th set
6th set
7th set
8th set
9th set
10th set
11th set
12th set

Memory rank sparing

The memory rank sparing feature disables the failed memory from the system configuration and activates a
rank sparing DIMM to replace the failed active DIMM.
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Lenovo System x3550 M5 Installation and Service Guide
CPU2
Number of installed
microprocessor
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2
Channel
DIMM connector population
sequence on the system board
1, 4
9, 12
2, 5
8, 11
3, 6
7, 10
1, 4
13, 16
9, 12
21, 24
2, 5
14, 17
8, 11
20, 23
3, 6
15, 18
7, 10
19, 22
Microprocessor 1
CPU1