Specifications

Cisco UCS C240 M4 High-Density Rack Server (Small Form Factor Disk Drive Model)
22
CONFIGURING the SERVER
■ Select the memory mirroring option (N01-MMIRROR) as shown in Tabl e 6 on page 20.
Caveats
■ System speed is dependent on how many DIMMs are populated per channel and the CPU
DIMM speed support. See
Table 7 for details.
■ The C240 M4 server supports four different memory reliability, availability, and
serviceability (RAS) modes:
— Independent Channel Mode
— Mirrored Channel Mode
— Lockstep Channel Mode
■ Below are the system level RAS Mode combination limitations:
— Mixing of Independent and Lockstep channel mode is not allowed per platform.
— Mixing of Non-Mirrored and Mirrored mode is not allowed per platform.
— Mixing of Lockstep and Mirrored mode is not allowed per platform.
■ Do not mix RDIMMs with LRDIMMs
■ Single-rank DIMMs can be mixed with dual-rank DIMMs in the same channel
■ Do not mix quad-rank DIMMs with single- or dual-rank DIMMs in the same channel
■ For best performance, observe the following:
— DIMMs with different timing parameters can be installed on different slots within the
same channel, but only timings that support the slowest DIMM will be applied to all.
NOTE: System performance is optimized when the DIMM type and quantity are equal
for both CPUs, and when all channels are filled equally across the CPUs in the server.
Table 7 DIMM Memory Speeds with Different CPUs
DIMM Speed DPC
1600-MHz Capable CPU 1866-MHz Capable CPU 2133-MHz Capable CPU
LRDIMM
(QR)
RDIMM (DR,
SR)
LRDIMM
(QR)
RDIMM (DR,
SR)
LRDIMM
(QR)
RDIMM (DR, SR)
2133 DIMM
1
Notes . . .
1. 2133-MHz DIMMs are the only offered and supported DIMMs for the C220 M4 server
1DPC 1600 1600 1866 1866 2133 2133
2DPC 1600 1600 1866 1866 2133 2133
3DPC 1600 1600 1600 1600 1866 1866 (16 GB DIMMs)
1600 (8 GB DIMMs)