Installing A Memory Module - Lenovo System x3550 M4 Installation And Service Manual

You can enable rank sparing memory in the Setup utility, select System Settings ➙ Memory. For more
information, see "Using the Setup utility" on page 95.
The maximum available memory is reduced when memory rank sparing mode is enabled.
The following diagram lists the DIMM connectors on each memory channel.
Ch2 Ch3
Figure 37. Connectors on each memory channel
Follow the installation sequence for rank sparing mode:
• Install at least one quad-rank DIMM in a channel.
• Install at least two single-rank or dual-rank DIMMs in a channel.
Table 8. Memory rank sparing mode DIMM population sequence
Number of DIMMs
First pair of DIMMs
Second pair of DIMMs
Third pair of DIMMs
Fourth pair of DIMMs
Fifth pair of DIMMs
Sixth pair of DIMMs
Seventh pair of DIMMs
Eighth pair of DIMMs
Ninth pair of DIMMs
Tenth pair of DIMMs
Eleventh pair of DIMMs
Twelfth pair of DIMMs
DIMM connectors 3, 6, 7, 10, 15, 18, 19, and 22 are not used in memory rank sparing mode when UDIMMs are
installed in the server.

Installing a memory module

Use this information to install a memory module.
Step 1. Read the safety information that begins on "Safety" on page v and "Installation guidelines" on page
31.
Step 2. Turn off the server and peripheral devices and disconnect the power cords and all external cables,
if necessary.
Step 3. Remove the cover (see "Removing the cover" on page 34).
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Lenovo System x3550 M4 Installation and Service Guide
Ch1 Ch0 Ch2 Ch3
Number of installed
microprocessor
1
1
1
1
1
1
2
2
2
2
2
2
Ch1 Ch0
DIMM connector
1, 2
4, 5
8, 9
11, 12
7, 10
3, 6
13, 14
16, 17
20, 21
23, 24
19, 22
15, 18