NOTE: Memory sparing does not offer protection against a multi-bit uncorrectable error.
NOTE: Both Advanced ECC/Lockstep and Optimizer modes support Memory Sparing.

Memory Mirroring

Memory Mirroring offers the strongest DIMM reliability mode compared to all other modes, providing improved
uncorrectable multi-bit failure protection. In a mirrored configuration, the total available system memory is one half of
the total installed physical memory. Half of the installed memory is used to mirror the active DIMMs. In the event of an
uncorrectable error, the system will switch over to the mirrored copy. This ensures SDDC and multi-bit protection.
Memory installation guidelines to support Memory Mirroring:
• Memory channel 1 (memory sockets A1 and B1) is disabled in this mode.
• Memory channels 2 and 3 must be populated.
• Only quad-rank DIMMs are supported.
• DIMMs installed must be identical in size, speed, and technology.
Sample Memory Configurations
The following tables show sample memory configurations that follow the appropriate memory guidelines stated in this
section.
NOTE: 16 GB quad-rank RDIMMs are not supported.
NOTE: 1R, 2R, and 4R in the following tables indicate single-, dual-, and quad-rank DIMMs respectively.
Table 1. Memory Configurations – Single Processor
System Capacity
(in GB)
DIMM Size (in
GB)
Number of
DIMMs
Organization and
Speed
DIMM Slot Population
2 2 1 1R x8, 1333 MT/s A1
4 2 2 1R x8, 1333 MT/s A1, A2
6 2 3 1R x8, 1333 MT/s A1, A2, A3
12 4 3 1R x4, 1333 MT/s
2R x8, 1333 MT/s
2R x8, 1600 MT/s
A1, A2, A3
24 8 3 2R x4, 1333 MT/s
2R x4, 1600 MT/s
A1, A2, A3
48 16 3 2R x4, 1333 MT/s
2R x4, 1600 MT/s
A1, A2, A3
96 32 3 4R x4, 1333 MT/s A1, A2, A3
Table 2. Memory Configurations – Two Processor
System Capacity (in
GB)
DIMM Size (in
GB)
Number of
DIMMs
Organization and
Speed
DIMM Slot Population
4 2 2 1R x8, 1333 MT/s A1, B1
8 2 4 1R x8, 1333 MT/s A1, A2, B1, B2
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