Dell PowerEdge R910 - Manual (Page 92)

92 Installing System Components
General Memory Module Installation Guidelines
To ensure optimal performance of your system, observe the following general
guidelines when configuring your system memory.
NOTE: Memory configurations that fail to observe these guidelines can prevent
your system from starting and producing any video output.
• All populated memory risers must have identical configurations.
• The memory configuration for each processor must be identical for
optimal performance.
• Memory modules of different sizes can be mixed (for example, 2 GB and
4 GB), but all populated channels must have identical configurations. The
mixed memory configurations must be of the size N+/-1.
• The memory speed depends on the processor bin.
• If quad-rank memory modules are mixed with single- or dual-rank
modules, the quad-rank modules must be installed in the sockets with the
white release levers.
• If memory modules with different speeds are installed, they operate at the
speed of the slowest installed memory module(s). The memory speeds are
also dependent on the processor bin.
Two memory risers are allocated to each processor. The number of channels
used and the allowable configurations depend on the memory mode selected.
The system supports memory mirroring if identical memory modules are
installed in both the risers. 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.
NOTE: Memory sparing and mirroring are enabled only when memory
configurations are greater than or equal to 64 GB.
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