Chapter 3
Maintaining the Server
Figure 3-12
DIMM Population Rules
Observe the following guidelines when installing or replacing DIMMs:
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•
•
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DIMM Slots and CPUs
A1
A2
B1
B2
C1
C2
CPU1
D1
D2
E1
E2
F1
F2
CPU2
Each CPU supports three memory channels.
CPU1 supports channels A, B, and C.
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CPU2 supports channels D, E, and F
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In a single-CPU system, the maximum number of DIMMs is six (only the six slots supported
Note
by CPU1).
Each channel has two DIMM slots (for example, channel A = slots A1 and A2).
A channel can operate with one or two DIMMs installed.
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If a channel has only one DIMM, populate slot 0 first (the blue slot).
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When both CPUs are installed, populate the DIMM slots of each CPU identically.
Fill blue slots in the channels first: A1, D1, B1, E1, C1, F1
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Fill black slots in the channels second: A2, D2, B2, E2, C2, F2
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Any DIMM installed in a DIMM socket for which the CPU is absent is not recognized. In a
single-CPU configuration, populate the channels for CPU1 only.
Installing or Replacing Server Components
Cisco UCS C24 Server Installation and Service Guide
3-21