Hardware Owner's Manual

208 Installing Blade Components
Non-Optimal Memory Configurations
System performance can be affected if your memory configuration does not
conform to the preceding installation guidelines. Your system may issue an
error message during start-up stating that your memory configuration is non-
optimal.
Memory Sparing Support – PowerEdge M605
Memory sparing is supported in single- or dual-processor systems that have one
of the fully populated memory configurations shown in Table 3-13.
The
memory sparing feature must be enabled in the Memory Information screen
of the System Setup program. See "Memory Settings Screen
" on page 140 . To
use memory sparing, you must disable node interleaving.
Memory sparing allocates only the first rank of memory of a DIMM. For a
single-rank DIMM, the entire capacity of the DIMM must be allocated for
sparing along with the adjacent single-rank DIMM to spare a memory
channel. For dual-rank DIMMs, two DIMMs are also required for sparing, but
as only the first rank of each DIMM is allocated, only half of a dual-rank
DIMM’s capacity is allocated for sparing. The second ranks on both DIMMs
are available memory. Table 3-13 shows how memory sparing splits the
available and spared memory in each memory module configuration.