Lenovo System x3550 M5, Installation And Service Manual

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• When you use memory mirrored channel, you must install a pair of DIMMs at a time. The two DIMMs in
each pair must be identical in size, type, and rank (single, dual, or quad), and organization, but not in
speed. The channels run at the speed of the slowest DIMM in any of the channels.
• 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.
Figure 87. 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
Number of installed
microprocessors DIMM connector population
sequence on the system board
One Microprocessor
1st set 1 1, 4
2nd set 1 9, 12
3rd set 1 2, 5
4th set 1 8, 11
5th set 1 3, 6
6th set 1 7, 10
Two Microprocessors
1st set 2 1, 4
2nd set 2 13, 16
3rd set 2 9, 12
4th set 2 21, 24
5th set 2 2, 5
6th set 2 14, 17
7th set 2 8, 11
8th set 2 20, 23
9th set 2 3, 6
10th set 2 15, 18
11th set 2 7, 10
12th set 2 19, 22
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Lenovo System x3550 M5 Installation and Service Guide