Datasheet

Cisco UCS B200 M3 Blade Server
16
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 with LRDIMMs
■ DIMMs for CPU 1 and CPU 2 (when populated) must always be configured identically.
■ Memory mirroring reduces the amount of available memory by 50% (quantity of DIMMs must
be even for mirroring).
■ By default, starting with UCSM 2.0.4, all DIMMs run in performance mode (1.5 V), which
yields 1600-MHz memory speeds provided:
— The DIMMs are 1600-MHz devices and the DIMM type is RDIMM. Note that LRDIMMs
may in some cases run at a maximum of 1333 or 1066 MHz even though they are
1600-MHz DIMMs.
— The CPUs chosen support 1600-MHz operation
— Memory is populated at less than 3 DIMMs per channel
For the DIMMs to run in power-savings mode (1.35 V) at 1333 MHz, go into the BIOS and
change the appropriate settings.
■ With 3 RDIMMs populated per channel, memory always runs at 1.5 V regardless if the BIOS
setting is power-savings mode (1.35 V) or performance mode (1.5 V).
■ With 3 LRDIMMs populated per channel, memory can operate at 1.5 V or 1.35 V, depending
on the BIOS setting.
■ With 3 DIMMs populated per channel, 8 GB and 16 GB 1600-MHz memory devices run at a
maximum speed of 1333 MHz. Other memory devices are limited to 1066 MHz operation
when populated at 3 DPC.
For more information regarding memory, see CPUs and DIMMs on page 36.