Memory Configurations; Memory Population Guidelines; Memory Ras Features - Dell PowerEdge R640 Manual

Table 7. Intel Xeon SP RDIMM/LRDIMM support
Type Ranks per
DIMM and
data width
RDIMM SR x 4
RDIMM SR x 8
RDIMM DR x 8
RDIMM DR x 4
LRDIMM QR x 4

Memory configurations

The PowerEdge R640 systems support flexible memory configurations 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 configuration. Each system has six
memory channels per processor, with each channel supporting up to two DIMMs.

Memory population guidelines

Both systems support a flexible memory configuration, according to the following population guidelines:
• Speed: If DIMMs of different 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 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
For more information on memory configuration 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 significant impact to
performance. RAS can decrease data loss and crashing due to errors. RAS helps in rapid, accurate diagnosis of faults that requires
servicing.
20 Memory
DIMM capacity (GB)
4 GB 8 GB
8 GB 16 GB
4 GB 8 GB
8 GB 16 GB
16 GB 32 GB
32 GB 64 GB
Speed (MT/s); Voltage (V)
Slot Per Channel (SPC) and DIMM Per Channel
(DPC)
1 Slot Per
Channel (SPC)
1DPC
16 GB 1.2 V
32 GB 2666
16 GB
32 GB
64 GB
-
2 Slots Per Channel (SPC)
1DPC 2DPC
1.2 V 1.2 V
2666 2440