Dell PowerEdge R640 - Memory population guidelines

Table 7. Intel Xeon SP RDIMM/LRDIMM support
Type Ranks per
DIMM and
data width
DIMM capacity (GB) Speed (MT/s); Voltage (V)
Slot Per Channel (SPC) and DIMM Per Channel
(DPC)
1 Slot Per
Channel (SPC)
2 Slots Per Channel (SPC)
1DPC 1DPC 2DPC
4 GB 8 GB 16 GB 1.2 V 1.2 V 1.2 V
RDIMM SR x 4 8 GB 16 GB 32 GB 2666 2666 2440
RDIMM SR x 8 4 GB 8 GB 16 GB
RDIMM DR x 8 8 GB 16 GB 32 GB
RDIMM DR x 4 16 GB 32 GB 64 GB
LRDIMM QR x 4 32 GB 64 GB -
Memory congurations
The PowerEdge R640 systems support exible memory congurations ranging from capacities of 8 GB (minimum), to 1536 GB (maximum).
The PowerEdge R640 supports up to 12 DIMMs per processor—up to 24 DIMMs in a dual-processor conguration. Each system has six
memory channels per processor, with each channel supporting up to two DIMMs.
Memory population guidelines
Both systems support a exible memory conguration, according to the following population guidelines:
• Speed: If DIMMs of dierent speeds are mixed, all channels across all processors operate at the common frequency of the slowest
DIMM.
• DIMM type: Maximum two types of DIMMs allowed per system and only NVDIMM-Ns and RDIMMs are supported. RDIMM with
LRDIMM and LRDIMM with NVDIMM-N 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
For more information on memory conguration and population, see the Dell EMC PowerEdge R640 Installation and Service Manual at
Dell.com/Support/Manuals.
Memory RAS features
Reliability, Availability, and Serviceability (RAS) features help keep the system online and operational without signicant impact to
performance. RAS can decrease data loss and crashing due to errors. RAS helps in rapid, accurate diagnosis of faults that requires
servicing.
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Memory