The table below lists the memory configuration and performance details of the PowerEdge R940xa, based on the quantity and type
of DIMMs per memory channel:
Table 8. Memory configuration and performance details
DIMM type
DIMM ranking
Capacity
DIMM rated voltage, speed
RDIMM
1R / 2R
8GB, 16GB, 32GB
DDR4 (1.2V), 2666MT/s
LRDIMM
4R / 8R
64GB, 128GB
DDR4 (1.2V), 2666MT/s
Memory configuration
The R940xa servers support flexible memory configurations ranging from capacities of 8GB (minimum) to 6144 GB(maximum). The
R940xa support up to 12 DIMMs per processor (up to 48 DIMMs in a four- processor configuration). Each server has 6 memory
channels per processor, with each channel supporting up to 2 DIMMs.
Both systems support a flexible memory configuration according to the following population rules:
•
Speed: If DIMMs of different speeds are mixed, all channels across all processors operate at the slowest DIMM's common
frequency.
•
DIMM type: Only one type of DIMM is allowed per system: RDIMM, or LRDIMM. These types 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
Table 9. Two different rank DIMMS configuration
DIMM type
RDIMM
LRDIMM
NVDIMM
RDIMM
Allowed
Not Allowed
Allowed
LRDIMM
Not Allowed
Allowed
Not Allowed
NVDIMM
Allowed
Not Allowed
Allowed
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 table below describes the memory RAS features supported for the PowerEdge R940xa:
Table 10. Supported RAS features
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.
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