19
Memory module installation guides
The list below are the PowerEdge T640's DIMM population requirements:
•
Speed: If DIMMs of
different
speeds are mixed, all channels across all processors operate at the slowest DIMM's common
frequency.
•
DIMM type: Max two types of DIMMs allowed per system and they have to be NVDIMMs and RDIMMS. RDIMM/LRDIMM and
LRDIMM/NVDIMM cannot be mixed.
•
DIMMs with
different
data widths can be mixed. For 14G, DIMMs with x4 and x8 data widths are supported and mixing is
allowed.
•
Can mix DIMMs with
different
capacities.
–
Population rules require the largest capacity DIMM be placed
first
(slot A1 populated
first,
then A2, and so on... The second
CPU mirrors the
first
CPU population).
–
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
Reliability, Availability, and Serviceability (RAS) features help keep the system online and operational without
significant
impact to
performance, and decreases data loss and crashing issues. RAS helps in rapid and accurate diagnosis of system faults.
Table 8. Supported RAS features
Memory Optimized
Baseline RAS features for highest performance optimization.
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.
NOTE: 16GB NVDIMMs are available post-initial release.
DIMM type
Description
Feature Description