Owners Manual

Table 10. Memory operating modes (continued)
Memory Operating Mode Description
NOTE: DCPMM supports only Optimizer mode.
Mirror Mode The Mirror Mode if enabled, the system maintains two identical copies of data in
memory, and 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.
This feature provides maximum reliability and enables the system to continue running
even during a catastrophic memory failure by switching over to the mirrored copy.
The installation guidelines to enable Mirror Mode require that the memory modules be
identical in size, speed, and technology, and they must be populated in sets of 6 per
processor.
Single Rank Spare Mode Single Rank Spare Mode allocates one rank per channel as a spare. If excessive
correctable errors occur in a rank or channel, while the operating system is running, they
are moved to the spare area to prevent errors from causing an uncorrectable failure.
Requires two or more ranks to be populated in each channel.
Multi Rank Spare Mode Multi Rank Spare Mode allocates two ranks per channel as a spare. If excessive
correctable errors occur in a rank or channel, while the operating system is running, they
are moved to the spare area to prevent errors from causing an uncorrectable failure.
Requires three or more ranks to be populated in each channel.
With single rank 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 24x 16 GB dual-rank memory
modules, the available system memory is: 3/4 (ranks/channel) × 24 (memory modules)
× 16 GB = 288 GB, and not 24 (memory modules) × 16 GB = 384 GB. For multi rank
sparing, the multiplier changes to 1/2 (ranks/channel).
NOTE: To use memory sparing, this feature must be enabled in the BIOS menu of
System Setup.
NOTE: Memory sparing does not offer protection against a multi-bit uncorrectable
error.
Dell Fault Resilient Mode The Dell Fault Resilient Mode if enabled, the BIOS creates an area of memory that is
fault resilient. This mode can be used by an OS that supports the feature to load critical
applications or enables the OS kernel to maximize system availability.
NOTE: This feature is only supported in Gold and Platinum Intel processors.
NOTE: Memory configuration has to be of same size DIMM, speed, and rank.
Optimizer 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.
● Dual processor: Populate the slots in round robin sequence starting with processor 1.
NOTE: Processor 1 and processor 2 population should match.
● Quad processor: Populate the slots in round robin sequence starting with processor 1.
NOTE: Processor 1, processor 2, processor 3, and processor 4 population should match.
Table 11. Memory population rules
Processor Configuration Memory population Memory population information
Dual processor (Start
with processor1.
processor1 and
processor 2
Optimized (Independent
channel) population order
A{1}, B{1},
A{2}, B{2},
A{3}, B{3},
A{4}, B{4},
Odd number of DIMM population per processor
is allowed.
NOTE: Odd number of DIMMs will result in
unbalanced memory configurations, which
60 Installing and removing sled components