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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OL-25760-01
DIMM Slots and CPUs
C1
C2
D1
D2
B2
B1
A2
A1
G1
G2
H1
H2
F2
F1
E2
E1
Each CPU supports four memory channels.
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CPU1 supports channels A, B, C, and D.
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CPU2 supports channels E, F, G, and H.
Each channel has two DIMM slots (for example, channel A = slots A1 and A2).
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A channel can operate with one or two DIMMs installed.
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If a channel has only one DIMM, populate slot 1 first (the blue slot).
When both CPUs are installed, populate the DIMM slots of each CPU identically.
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Fill blue slots in the channels first: A1, E1, B1, F1, C1, G1, D1, H1
Fill black slots in the channels second: A2, E2, B2, F2, C2, G2, D2, H2
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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.
CPU1
CPU2
Cisco UCS C220 Server Installation and Service Guide
Installing or Replacing Server Components
3-19