– Maximum of two different capacity DIMMs allowed in a system
•
Can mix DIMMs with different ranks.
– Maximum of two different rank DIMMs allowed in a system
Memory RAS features
Reliability, Availability, and Serviceability (RAS) features help keep the system online and operational without significant impact to
performance and can decrease data loss and crashing due to errors. RAS aids in rapid, accurate diagnosis of faults which require
service.
The following table describes the memory RAS features supported on the PowerEdge R740xd2:
Feature
Description
Dense configuration optimized profile
Increased memory reliability can be a result from this selectable
platform profile that adjusts parameters to reduce faults
regarding refresh rates, speed, temperature and voltage
Memory demand and patrol scrubbing
Demand scrubbing is the ability to write corrected data back to
the memory once a correctable error is detected on a read
transaction. Patrol scrubbing proactively searches the system
memory, repairing correctable errors.
Recovery from single DRAM device failure (SDDC)
Recovery from Single DRAM Device Failure (SDDC) provides
error checking and correction that protects against any single
memory chip failure as well as multi-bit errors from any portion
of a single memory chip.
Failed DIMM isolation
This feature provides the ability to identify a specific failing
DIMM channel pair, thereby enabling the user to replace only the
failed DIMM pair.
Memory mirroring
Memory mirroring is a method of keeping a duplicate (secondary
or mirrored) copy of the contents of memory as a redundant
backup for use if the primary intra-socket memory fails. The
mirrored copy of the memory is stored in memory of the same
processor socket.
Memory address parity protection
This feature provides the ability to detect transient errors on the
address lines of the DDR channel.
Memory sparing (rank)
Memory sparing allocates one rank per channel as a spare. If
excessive correctable errors occur in a rank or channel, they are
moved to the spare area while the operating system is running to
prevent the errors from causing an uncorrectable failure.
Memory thermal throttling
This feature helps to optimize power/performance and can also
be used to prevent DIMMs from overheating.
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