Memory Speed Limitations; Sparing; Mirroring; Raid - Dell PowerEdge R910 Technical Manual

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
Clock gating (CKE) to conserve power when DIMMs are not accessed (DIMMs enter a low power
self-refresh mode)
2

I C access to SPD EEPROM for access to RDIMM thermal sensors

Single-Bit Error Correction

SDDC (Single Device Data Correction — x4 or x8 devices)

Support for Closed Loop Thermal Management on RDIMMs

Multi-Bit Error Detection

Support for Memory Mirroring in limited configurations

Support for Memory (Rank) Sparing in limited configurations

7.4 Memory Speed Limitations

The memory frequency is determined by a variety of inputs:

Speed of the DIMMs

Speed supported by the processor (note the DDR3 speed is 1/6 the frequency of the SMI link)

BIOS can limit frequency to DDR3 800 MT/s based on user power savings configuration in the
SETUP menu
The PowerEdge R910 supports DDR3 1333 MT/s DIMMs. Some processor models will have lower SMI
link speeds resulting in slower DDR3 buses. The supported frequencies are as follows:

SMI link speed at 4.8GT/sec => DDR3 800 MT/s

SMI link speed of 5.86 GT/sec => DDR3 978 MT/s

SMI link speed of 6.4 GT/sec => DDR3 1067 MT/s

7.5 Sparing

For rank sparing, one rank on each lockstep Intel 7500 Scalable Memory Interconnect (SMI) pair will
be reserved as a spare, and in the event that another rank exceeds a threshold of correctable ECC
errors, the "failing" rank will be copied to the spare. Once that operation is complete, the failed
rank will be disabled.

7.6 Mirroring

For mirroring, the PowerEdge R910 supports 2P/4P configurations for 64GB and larger only. When
mirroring is enabled, only half of the physical memory is visible to the system software. A full copy
of the memory is maintained, and in the event of an uncorrectable error, the system will switch over
to the mirrored copy. The R910 uses intra-socket mirroring.

7.7 RAID

The PowerEdge R910 does not support memory RAID.

7.8 Supported Configurations

See the System Memory section in the Installing System Components chapter in the Dell PowerEdge
R910 Systems Hardware Owner's Manual on Support.Dell.com/Manuals.
Dell PowerEdge R910 Technical Guide 28