Dell PowerEdge R820 - Entering System Setup

18 PowerEdge R820 Technical Guide
The R820 supports the DIMMs listed in Table 8. For the latest information on supported memory,
visit Dell.com/PowerEdge.
Table 8. DIMMs supported
Capacity
(GB)
Speed
(MT/s)
Type
Ranks per
DIMM
Data
width
SDDC support
Voltage
4
1600
RDIMM
1
x8
Advanced ECC
1.35
8
1600
RDIMM
1
x4
All modes
1.35
16
1600
RDIMM
2
x4
All modes
1.35
32
1333
RDIMM
4
x4
All modes
1.35
32
1333
LRDIMM
4
x4
All modes
1.35
32
1600
LRDIMM
4
x4
All modes
1.35
Memory configurations
The R820 server supports flexible memory configurations ranging from capacities of 4GB to
1.5TB. The R820 supports up to 12 DIMMs per processor (up to 48 DIMMs in a four-processor
configuration). The R820 has four memory channels per processor, with each channel supporting
up to three DIMMs.
The R820 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 is allowed per system. UDIMM, RDIMM and LRDIMM cannot
be mixed.
The following additional memory population guidelines apply to the R820:
 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, see the Dell PowerEdge R820 Owner’s Manual on
Dell.com/Support/Manuals.
Memory speed
The R820 supports memory speeds of up to 1600MT/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 systems run 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.
Visit the PowerEdge memory page on Dell.com for the latest memory configuration and
performance details for the R820 based on the population of the number and type of DIMMs per
memory channel.