Dell PowerEdge R410 Hardware Owner's Manual page 121

Memory Mirroring Support
The system supports memory mirroring if identical memory modules are
installed in the two channels closest to the processor (memory should not be
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.
Optimizer (Independent Channel) Mode
In this mode, all three channels are populated with identical memory
modules. This mode permits a larger total memory capacity but does not
support SDDC with x8-based memory modules.
A minimal single-channel configuration of one 1-GB memory module per
processor is also supported in this mode.
Table 3-2 and Table 3-3 show sample memory configurations that follow the
appropriate memory guidelines stated in this section. The samples show
identical memory-module configurations and their the physical and available
memory totals. The tables do not show mixed or quad-rank memory-module
configurations, nor do they address the memory speed considerations of any
configuration.
Table 3-2. Sample RDIMM Single- and Dual-Rank Memory Configurations
(Per Processor)
Memory
Memory Module
Mode Size
Optimizer 1-GB
Memory
Sockets
4 1 2 3 Physical
Memory
(GB)
X
X X
X X X
X X
X X X X
Single Processor
Available
Memory
(GB)
1 all
2
3
2
4
Installing System Components
Dual Processor
Physical Available
Memory Memory
(GB) (GB)
2 all
4
6
4
8
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