Datasheet

Cisco UCS Cisco UCS C220 M3 High-Density Rack Server (Large Form Factor Hard Disk Drive Model)

CONFIGURING the SERVER

Caveats

■ For optimum performance, do not mix DIMMs with different frequencies. If you mix DIMM

frequencies, the system defaults to the lower frequency.

■ Do not mix RDIMMs and LRDIMMs

■ DIMMs for CPU 1 and CPU 2 (when populated) must always be configured identically.

■ The server supports 1 or 2 DIMMs per channel for single- or dual-rank RDIMMs.

■ The server supports 1 or 2 DIMMs per channel for quad-rank LRDIMMs.

■ The server supports registered DIMMs (RDIMMs) or load-reduced DIMMS (LRDIMMs), however,

do not mix RDIMMs and LRDIMMs in a server.

■ When using mirroring, DIMMs must be installed in identical pairs across paired DDR3 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 and in C and D can be

different.

■ Non-ECC DIMMs are not supported.

■ Memory mirroring reduces the amount of available memory by 50% (quantity of DIMMs must

be even for mirroring).

■ When single- and dual-rank DIMMs are populated for 2DPC, always populate the dual rank

DIMM in the blue DIMM slot, and the single-rank DIMM in the black DIMM slot (only the 4GB

DIMMs are single-rank).

■ By default, all DIMMs run at 1.35 V, which yields 1333-MHz memory speeds. To run the

memory DIMMS at 1600 MHz, you need to go into the BIOS or set the policy with UCSM

(service profile) to run in Performance Mode. This forces the DIMMs to operate at 1.5 V and

yields 1600-MHz speeds, provided:

— The DIMMs are 1600-MHz devices and the DIMM type is RDIMM

— The CPUs chosen support 1600-MHz operation.

For more information regarding memory, see CPUs and DIMMs, page 49.

NOTE: 32 GB LRDIMMs run at a maximum speed of 1333 MHz for 1DPC and 2DPC even

though their specified maximum speed is 1600 MHz.