Dell EMC PowerEdge R940xa - Memory Configuration; Memory RAS Features

The table below lists the memory conguration and performance details of the PowerEdge R940xa, based on the quantity and type
of DIMMs per memory channel:
Table 8. Memory conguration 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 conguration
The R940xa servers support exible memory congurations 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 conguration). Each server has 6 memory
channels per processor, with each channel supporting up to 2 DIMMs.
Both systems support a exible memory conguration according to the following population rules:
• Speed: If DIMMs of dierent 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 dierent data widths can be mixed. For 14G, DIMMs with x4 and x8 data widths are supported and mixing is
allowed.
• Can mix DIMMs with dierent capacities.
– Population rules require the largest capacity DIMM be placed rst (slot A1 populated rst, then A2, and so on... The second
CPU mirrors the rst CPU population).
– Maximum of two dierent capacity DIMMs allowed in a system
• Can mix DIMMs with dierent ranks.
– Maximum of two dierent rank DIMMs allowed in a system
Table 9. Two dierent rank DIMMS conguration
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 signicant 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 conguration optimized prole Increased memory reliability can be a result from this selectable
platform prole 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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