Lenovo System x3550 M4 Installation And Service Manual page 236

Ch2 Ch3
Figure 139. 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 23. 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.
Replacing a memory module
Use this information to install a memory module.
To install a memory module, complete the following steps:
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 194).
Step 4. Remove the air baffle (see "Removing the air baffle" on page 196).
Step 5. Carefully open the retaining clips on each end of the DIMM connector and remove the DIMM.
Attention: To avoid breaking the retaining clips or damaging the DIMM connectors, open and
close the clips gently.
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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