Owners Manual

• DIMMs installed in memory sockets with white release levers must be identical and the same rule
applies for sockets with black release levers. This ensures that identical DIMMs are installed in
matched pair —for example, A1 with A2, A3 with A4, A5 with A6, and so on.
Memory optimized (independent channel) mode
This mode supports Single Device Data Correction (SDDC) only for memory modules that use x4 device
width. It does not impose any specific slot population requirements.
Memory sparing
NOTE: To use memory sparing, this feature must be enabled in System Setup.
In this mode, one rank per channel is reserved as a spare. If persistent correctable errors are detected on
a rank, the data from this rank is copied to the spare rank, and the failed rank is disabled.
With memory sparing enabled, the system memory available to the operating system is reduced by one
rank per channel. For example, in a dual-processor configuration with sixteen 4 GB single-rank memory
modules, the available system memory is: 3/4 (ranks/channel) × 16 (memory modules) × 4 GB = 48 GB,
and not 16 (memory modules) × 4 GB = 64 GB.
NOTE: Memory sparing does not offer protection against a multi-bit uncorrectable error.
NOTE: Both Advanced ECC/Lockstep and Optimizer modes support memory sparing.
Sample memory configurations
The following tables show sample memory configurations for two processor configurations that follow
the appropriate memory guidelines.
NOTE: 1R and 2R in the following tables indicate single- and dual-rank DIMMs respectively.
Table 30. Memory configurations—two processors
System
Capacity
(in GB)
DIMM Size
(in GB)
Number of
DIMMs
DIMM Rank,
Organization, and
Frequency
DIMM Slot Population
16 8 2
1R, x8, 2400 MT/s A1,B1
32 8 4
1R, x8, 2400 MT/s A1, A2, B1, B2
16 2
2R, x8, 2400 MT/s A1, B1
48 8 6
1R, x8, 2400 MT/s A1, A2, A3, B1, B2, B3
64 8 8
1R, x8, 2400 MT/s A1, A2, A3, A4, B1, B2, B3,
B4
16 4
2R, x8, 2400 MT/s A1, A2, B1, B2
32 2
2R, x4, 2400 MT/s A1, B1
96 8 12
1R, x8, 2400 MT/s A1, A2, A3, A4, A5, A6, B1,
B2, B3, B4, B5, B6
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