Specifications

Cisco UCS C240 M4 High-Density Rack Server (Small Form Factor Disk Drive Model)
CONFIGURING the SERVER
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As a consequence, faster DIMMs will be operated at timings supported by the slowest
DIMM populated.
— When one DIMM is used, it must be populated in DIMM slot 1 (farthest away from the
CPU) of a given channel.
— When single, dual or quad rank DIMMs are populated for 2DPC or 3DPC, always
populate the higher number rank DIMM first (starting from the farthest slot). For a
3DPC example, first populate with quad-rank DIMMs in the DIMM slot 1. Then
dual-rank DIMMs in the DIMM 2 slot. Then single-rank DIMMs in the DIMM 3slot.
■ DIMMs for CPU 1 and CPU 2 (when populated) must always be configured identically.
■ When using mirroring, DIMMs must be installed in identical pairs across paired DDR4 buses.
That is, mirrored pairs in channels A and B must be identical and pairs in channels C and D
must be identical. However, the DIMMs used in channels A and B can be different from those
in channels C and D.
■ Memory mirroring reduces the amount of available memory by 50% (quantity of DIMMs must
be even for mirroring).
■ Non-ECC DIMMs are not supported.
■ Pairs of DIMMs (A1/B1, A2/B2, etc) MUST be the exact same (same PID, rev, DIMM loading
order)
■ Cisco memory from previous generation servers (DDR3) is not compatible with this server
For more information regarding memory, see CPUs and DIMMs, page 63.