Owners Manual

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.
Memory mirroring
Memory mirroring offers the strongest memory module 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 memory modules. In the event of an
uncorrectable error, the system switches over to the mirrored copy. This ensures SDDC and multi-bit protection.
The installation guidelines for memory modules are as follows:
● Memory modules must be identical in size, speed, and technology.
● DIMMs installed in memory sockets with white release tabs must be identical and similar rule applies for sockets with black
release tabs. This ensures that identical DIMMs are installed in matched pairs—for example, A1 with A2, A3 with A4.
NOTE:
Mirroring and Advanced ECC modes require minimum of two DIMMs per CPU and must be populated in pairs of
either two or four DIMMs per CPU.
Table 38. Processor configuration
Processor Configuration Memory population rules Memory population information
Single CPU Memory population order {1,2}, {3,4} See Memory mirroring note
Sample memory configurations
The following tables show sample memory configurations for one and 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 39. Memory configurations—single processor (continued)
System
Capacity (in
GB)
DIMM Size
(in GB)
Number of
DIMMs
DIMM Rank,
Organization, and
Frequency
DIMM Slot Population
4 4 1
1R, x8, 2400 MT/s,
1R, x8, 2133 MT/s,
1R, x8, 1866 MT/s
A1
8 4 2
1R, x8, 2400 MT/s,
1R, x8, 2133 MT/s,
A1, A2
Installing and removing system components 83