Dell PowerEdge R740xd2 EMC Installation and Service Manual - Page 95

Optimizer Mode, Table 12. Memory operating modes continued, Table 13. Memory population rules

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Table 12. Memory operating modes (continued) Memory Operating Mode Description 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 sixteen 16 GB dual-rank memory modules, the available system memory: 16 GB x 16(memory modules) - 8GB(1 rank sparing/channel) x 12(channel) = 256 GB - 96 GB = 160 GB For multi rank sparing, in a dual-processor configuration with sixteen 64 GB quad-rank memory modules, the available system memory: 64 GB x 16(memory modules) - 32 GB(2 rank sparing/ channel) x 12 (channel) = 1024 GB - 384 GB = 640 GB 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. 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. Table 13. Memory population rules Processor Configuration Single processor Optimizer (Independent channel) population order Memory population 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 Mirror population order {1, 2, 3, 4, 5, 6} Memory population information • Populate in this order, odd amount allowed. • Odd number of DIMM population is allowed. NOTE: Odd number of DIMMs will result in unbalanced memory configurations, which in turn will result in performance loss. It is recommended to populate all memory channels identically with identical DIMMs for best performance. • Optimizer population order is not traditional for 4 and 8 DIMM installations of single processor. ○ For 4 DIMMs: A1, A2, A4, A5 ○ For 8 DIMMs: A1, A2, A4, A5, A7, A8, A9, A10 Mirroring is supported with 6 DIMM slots per processor. Installing and removing system components 95

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Table 12. Memory operating modes (continued)
Memory Operating Mode
Description
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 sixteen 16 GB
dual-rank memory modules, the available system memory: 16 GB x
16(memory modules) - 8GB(1 rank sparing/channel) x 12(channel)
= 256 GB - 96 GB = 160 GB
For multi rank sparing, in a dual-processor configuration with
sixteen 64 GB quad-rank memory modules, the available system
memory: 64 GB x 16(memory modules) - 32 GB(2 rank sparing/
channel) x 12 (channel) = 1024 GB - 384 GB = 640 GB
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.
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.
Table 13. Memory population rules
Processor
Configuration
Memory population
Memory population information
Single processor
Optimizer (Independent channel)
population order
1, 2, 3, 4, 5, 6, 7, 8, 9, 10
•
Populate in this order, odd
amount allowed.
•
Odd number of DIMM population
is allowed.
NOTE:
Odd number of
DIMMs will result in
unbalanced memory
configurations, which in
turn will result in
performance loss. It is
recommended to populate
all memory channels
identically with identical
DIMMs for best
performance.
•
Optimizer population order is not
traditional for 4 and 8 DIMM
installations of single processor.
○
For 4 DIMMs: A1, A2, A4, A5
○
For 8 DIMMs: A1, A2, A4, A5,
A7, A8, A9, A10
Mirror population order
{1, 2, 3, 4, 5, 6}
Mirroring is supported with 6 DIMM
slots per processor.
Installing and removing system components
95