Specifications

21 PowerEdge T420 Technical Guide
The T420 supports the DIMMs listed in Table 9. For the latest information on supported memory,
visit Dell.com/PowerEdge.
Table 9. DIMMs supported
Capacity
(GB)
Speed
(MT/s)
Type
Ranks per
DIMM
Data
width
SDDC support
Voltage
2
1600
UDIMM
1
x8
Advanced ECC
1.35
2
1600
RDIMM
1
x8
Advanced ECC
1.35
4
1600
RDIMM
2
x8
Advanced ECC
1.35
4
1600
UDIMM
1
x8
Advanced ECC
1.35
4
1600
UDIMM
2
x8
Advanced ECC
1.35
4
1600
RDIMM
1
x8
Advanced ECC
1.35
8
1600
RDIMM
1
x4
All modes
1.35
8
1600
RDIMM
2
x4
All modes
1.35
16
1600
RDIMM
2
x4
All modes
1.35
16
1600
RDIMM
2
x4
All modes
1.35
32
1333
RDIMM
4
x4
All modes
1.35
Memory configurations
The T420 supports flexible memory configurations ranging from capacities of 2GB to 384GB. The
system supports up to six DIMMs per processor (up to 12 DIMMs in a two-processor configuration).
The T420 has three memory channels per processor, with each channel supporting up to two
DIMMs.
The T420 supports a flexible memory configuration according to these 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 can be used in a system. UDIMMs and RDIMMs cannot be
mixed.
The following additional memory population guidelines apply to the T420:
 Up to two quad-rank (QR), dual-rank (DR), or single-rank (SR) DIMMs may be populated 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, see the Dell PowerEdge T420 Systems Owner’s
Manual on Dell.com/Support/Manuals.
Memory speed
The T420 supports memory speeds of up to 1600MT/s, depending on the DIMM types installed and
the configuration. The loading within a channel significantly affects memory speed.
Table 10 illustrates the maximum achievable speed of the Intel Xeon processor E5-2400 and E5-
2400 v2 product families based on memory loads.
 Green boxes are defaults for performance per watt