DELL DL2100 User Manual

Page of 200
124
Installing System Components
Mode-Specific Guidelines
Three memory channels are allocated to each processor. The number of 
channels and allowable configurations depend on the memory mode selected.
Advanced ECC (Lockstep) Mode Support
In this configuration, the two channels closest to the processor are combined 
to form one 128-bit channel. This mode supports SDDC for both x4- and x8- 
based memory modules. Memory modules must be identical in size, speed, 
and technology in corresponding slots.
Memory Mirroring Support 
The system supports memory mirroring if identical memory modules are 
installed in the two channels closest to the processor (memory is 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.
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 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.