Dell PowerEdge M420 Technical Manual page 19

The M420 server supports the DIMMs listed in Table 7. For the latest information on supported
memory, visit Dell.com.
Capacity
(GB)
2
2
4
4
4
4
8
8
16
16
32
The M420 server supports flexible memory configurations ranging from capacities of 2GB to
192GB, and up to 3 DIMMs per processor (up to 6 DIMMs in a dual-processor configuration). Each
processor has three memory channels, with each channel supporting a single DIMM.
The M420 supports 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.
The following additional memory-population guidelines also apply to the M420:
A single quad-rank (QR) DIMM, dual-rank (DR), or single-rank (SR) DIMM may be populated on

each channel.
 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
Systems Owner's Manual
The M420 supports memory speeds of 1600MT/s, 1333MT/s, 1066MT/s, and 800MT/s depending on
the DIMM types installed and the configuration. All memory on all processors and channels run at
the same speed and voltage. By default, the system runs at the highest speed for the channel with
the lowest DIMM voltage and speed. The operating speed of the memory is also determined by the
maximum speed supported by the processor, the speed settings in the BIOS, and the operating
voltage of the system.
PowerEdge M420 Technical Guide
19
Ranks
Speed
Type
(MT/s)
DIMM
1333 RDIMM
1600 RDIMM
1333 RDIMM
1333 RDIMM
1600 RDIMM
1600 UDIMM
1333 RDIMM
1600 RDIMM
1600 RDIMM
1333 RDIMM
1333 RDIMM
on Support.Dell.com/Manuals.
Data
per SDDC support
width
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
Voltage
1.35
1.35
1.35
1.35
1.35
1.35
1.35
1.35
1.35
1.35
1.35
Dell PowerEdge M420