Dimm Installation Sequence; Memory Mirrored Channel - Lenovo x3550 M5 Installation And Service Manual

Microprocessor 2
Figure 83. DIMM connectors location

DIMM installation sequence

Depending on the server model, the server may come with a minimum of one 2 GB or 4 GB DIMM installed
in slot 1. When you install additional DIMMs, install them in the order shown in the following table to
optimize system performance.
In general, all four channels on the memory interface for each microprocessor can be populated in any order
and have no matching requirements.
Table 27. Normal mode DIMM installation sequence
Number of installed
microprocessors
One microprocessor installed
Two microprocessors installed

Memory mirrored channel

Memory mirrored channel mode replicates and stores data on two pairs of DIMMs within two channels
simultaneously.
If a failure occurs, the memory controller switches from the primary pair of memory DIMMs to the backup
pair of DIMMs. To enable memory mirrored channel through the Setup utility, select System Settings ➙
Memory. For more information, see "Using the Setup utility" on page 36. When you use the memory
mirrored channel feature, consider the following information:
• 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.
CPU2
DIMM connector population sequence
1, 4, 9, 12, 2, 5, 8, 11, 3, 6, 7, 10
1, 13, 4, 16, 9, 21, 12, 24, 2, 14, 5, 17, 8, 20, 11, 23, 3, 15, 6, 18, 7, 19, 10, 22
Microprocessor 1
CPU1
.
Chapter 5 Removing and replacing components
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