User Manual

Dell
PowerEdge R610 Technical Guide 30
7.4 DIMM Slots
The PowerEdge R610 has 12 DIMM slots for memory. It does not have any riser cards for DIMM
population.
The first DIMM slot in each channel is color-coded with white ejection tabs for ease of installation.
The DIMM sockets are placed 450 mils (11.43 mm) apart, center-to-center to provide enough space
for sufficient airflow to cool stacked DIMMs.
7.5 Low Voltage DIMMs
With the introduction of the Intel
®
Xeon
®
processor 5600 series, low voltage (LV) DIMMs have been
added for selected memory configurations for the PowerEdge R610. Only this processor series
supports operating DIMMs at the lower voltage (1.35V, also referred to as DDR3L). The Intel Xeon
5500 processor series does not support low voltage operation. However, due to the backwards-
compatible nature of low voltage DIMMs, they can be operated at 1.5V. Therefore, DDR3L DIMMs can
be used in systems with either processor series, and the platform will automatically choose the
appropriate operating voltage based on the processor populated. DDR3L DIMMs will be qualified and
available for use with Intel Xeon 5500 processor series mid-year 2011. Contact your Dell Sales
Representative or visit Dell.com for more information.
LV DIMMs operate at 1.35V, creating power savings vs. standard memory which operates at 1.5V. In
order to achieve power savings, all DIMMs in the system must be of the LV type. If the system detects
a mixture of standard and LV DIMMs, the BIOS will operate all memory at 1.5V. When operating at
the lower voltage, additional frequency and population restrictions can take effect. For example, 3
DIMMs per channel operation is not supported at low voltage.
The DDR3L standard is completely backwards-compatible at standard voltage. DDR3L DIMMs can
operate at 1.5V without any limitations beyond standard voltage DDR3 DIMMs. As part of the addition
of LV DIMMs, the platform has certain default behaviors. Whenever possible, if there is no
performance degradation, the platform will default to 1.35V operation when using DDR3L DIMMs. In
certain cases, where a configuration is populated that cannot support 1.35V or a performance
degradation would result, the platform defaults to 1.5V operation. There are also options to override
default voltage within allowed limits.
7.6 Mirroring
The R610 system supports memory mirroring if identical memory modules are installed in the two
channels closest to the processor (memory not installed in the farthest channel). Mirroring must be
enabled in the System Setup program. In a mirrored configuration, the total available system
memory is one-half of the total installed physical memory.
7.7 Sparing
Systems with the Intel Xeon processor 5600 series support memory sparing. Sparing requires identical
memory installed in all three channels. One of the three channels is considered the Spare Channel,
and two-thirds of the total installed memory is usable and is the amount reported during POST and in
BIOS setup.