Dimm Installation Sequence; Memory Mirrored Channel - Lenovo System x3550 M4 Installation And Service Manual

1. You can install DIMMs for microprocessor 2 as soon as you install microprocessor 2; you do not have to
wait until all of the DIMM slots for microprocessor 1 are filled.
2. DIMM slots 13-24 are reserved for microprocessor 2; thus, DIMM slots 13-24 are enabled when
microprocessor 2 is installed.
The following illustration shows the location of the DIMM connectors on the system board.
Ch2 Ch3
Figure 35. 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 three channels on the memory interface for each microprocessor can be populated in any
order and have no matching requirements.
Table 6. Normal mode DIMM installation sequence
Number of installed
microprocessor
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.
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Lenovo System x3550 M4 Installation and Service Guide
Ch2 Ch3
Ch1 Ch0
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
Ch1 Ch0