Supported Memory - Dell PowerEdge External OEMR XL R720XD Technical Manual

Table 8 lists the DIMMs supported on the R720 and R720xd. For the latest information on supported
memory, visit Dell.com.
Only
Capacity
(GB)
2
2
2
4
4
4
4
8
8
16
16
32
32
The R720 and R720xd servers support flexible memory configurations ranging from capacities of
2GB (minimum) to 768GB (maximum). The R720 and R720xd support up to 12 DIMMs per processor
(up to 24 DIMMs in a dual-processor configuration). Each server has 4 memory channels per
processor, with each channel supporting up to 3 DIMMs.
Both systems support a flexible memory configuration, according to the following basic 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: UDIMM, RDIMM, or LRDIMM. These
types cannot be mixed.
The following additional memory-population guidelines apply to the R720 and R720xd:

Up to two quad-rank (QR) DIMMs and up to three dual-rank (DR) or single-rank (SR) DIMMs may
be populated per channel. Although an LRDIMM is physically a QR DIMM, logic on the LRDIMM
can make it appear as a DR DIMM to the system, allowing up to three LDRIMMs per channel.

DIMMs must be installed in each channel, starting with the DIMM farthest from the processor.

DIMMs should be installed with largest rank count to smallest. For example, if DR DIMMS are
mixed with SR DIMMs, DR DIMMS should be placed in the lowest DIMM slots, followed by the SR
DIMMs.
For more information on memory configuration and population, see the
R720xd Owner's Manual
PowerEdge R720 and R720xd Technical Guide
24
Speed Ranks per
Type
(MT/s) DIMM
1333 RDIMM
1333 UDIMM
1600 RDIMM
1333 RDIMM
1333 RDIMM
1333 UDIMM
1600 RDIMM
1333 RDIMM
1600 RDIMM
1333 RDIMM
1600 RDIMM
1333 LRDIMM
1333 RDIMM
on Support.Dell.com/Manuals.
Data
SDDC support
width
1 x8 Advanced ECC
1 x8 Advanced ECC
1 x8 Advanced ECC
2 x8 Advanced ECC
1 x4 All modes
2 x8 Advanced ECC
2 x8 Advanced ECC
2 x4 All modes
2 x4 All modes
2 x4 All modes
2 x4 All modes
4 x4 All modes
4 x4 All modes
Voltage
1.35
1.35
1.5
1.35
1.35
1.35
1.5
1.35
1.5
1.35
1.5
1.35
1.35
Dell PowerEdge R720 and