Cisco UCS C210 Installation And Service Manual page 61

Chapter
Memory Population Rules
When considering the memory configuration of your server, you should consider the following items:
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Note
Low-Voltage DIMM Considerations (Generation M2 Only)
The Generation M2 of this server can be ordered with low-voltage (1.35 V) DIMMs or standard-voltage
(1.5 V) DIMMs. Note the following considerations:
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Note
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Enter the BIOS setup utility by pressing the F2 key when prompted during bootup.
Step 1
Select the Advanced tab.
Step 2
Select Low Voltage DDR Mode.
Step 3
In the pop-up window, select either Power Saving Mode or Performance Mode.
Step 4
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Press F10 to save your changes and exit the setup utility.
Step 5
OL-20887-02
DIMMs within the server should all be the same type, speed, and size. Do not mix different sized
DIMMs or DIMMs with different clock rates in the same server. Doing so causes the system to set
the memory system speed to that of the slowest installed DIMMs.
DIMMs can be used either in a one DIMM per Channel (1DPC) configuration or in a two DIMMs
per Channel (2DPC) configuration.
There are blue and black DIMM slots. Populate blue slots in a bank first.
(Generation M2 only) Low-voltage (1.35 V) DIMM and standard-voltage DIMM (1.5 V) can be
mixed in the same server. Note that this causes the system BIOS to default to standard-voltage
operation (Performance Mode). See
page 3-23.
Low voltage DIMMs are supported in Generation M2 servers only.
Low-voltage DIMMs within the server must have the identical manufacturer, type, speed, and size.
Low-voltage DIMMs and standard-voltage DIMMs can be mixed in the same server. Note that this
causes the system BIOS to default to standard-voltage operation (Performance Mode). That is, the
server cannot operate in Power Saving Mode unless all DIMMs are low-voltage DIMMs.
CPUs that have a maximum memory frequency less than 1333 MHz support LV DIMMs
operating in Power saving Mode only, and do not support Performance mode. However, if your
server has one of these CPUs, monitoring output for LV DIMMs will show identical voltages for
both Power Saving Mode and Performance Mode. In this case, Performance Mode is not active
and its fields only mirror the values from the Power Savings Mode fields.
In Generation M2 only, there is a setting in the BIOS Setup utility that you can use to change the
DDR memory mode when the server has all low-voltage DIMMs installed. To access this setting,
follow these steps:
Power Saving Mode–Prioritizes low-voltage memory operation. This setting is available only if all
DIMMs installed are low-voltage DIMMs.
Performance Mode–Prioritizes performance memory operation. If you mix low-voltage DIMM pairs
with standard-voltage DIMM pairs, the system defaults to this setting.
Low-Voltage DIMM Considerations (Generation M2 Only),
Cisco UCS C210 Server Installation and Service Guide
3-23