BX924 S4
Upgrade and Maintenance Manual
149
Main memory
– If memory modules with different capacities are used:
– Populate modules with higher capacities first.
– Within a channel, populate modules in descending order of capacity.
– If memory modules with different speeds are used, the lowest clock rate
applies for all DIMMs.
Regardless of the mode, all DIMMs will run at the highest common
frequency that is allowed by the SPD Data of the DIMMs and the maximum
speed of the selected configuration.
– Mixing RDIMMs or LRDIMMs is not allowed.
– Mixing ECC and non-ECC DIMMs is not allowed.
– Mixing of quad-rank DIMMs in one channel and three DIMMs in another
channel (3DPC) on the same CPU is not allowed. This is not valid for
LRDIMMs.
Figure 52: Overview of the slot numbering and the memory channels
CPU 1
CPU 2
Front
Channel B
Channel A
DIMM 3B
DIMM 1B
DIMM 3A
DIMM 2A
DIMM 1A
DIMM 2B
Channel H
Channel G
DIMM 3H
DIMM 1H
DIMM 3G
DIMM 2G
DIMM 1G
DIMM 2H
Channel E
Channel F
DIMM 1E
DIMM 3E
DIMM 1F
DIMM 2F
DIMM 3F
DIMM 2E
Channel C
Channel D
DIMM 1C
DIMM 3C
DIMM 1D
DIMM 2D
DIMM 3D
DIMM 2C