Flexible Memory Configuration; Memory Speed; Table 8. Memory Speed Capabilities - Dell PowerEdge M620 Technical Manual

Flexible memory configuration

The M620 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.

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 M620:

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
Systems Owner's Manual

Memory speed

The M620 supports memory speeds of 1866MT/s, 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.
Table 8 lists the memory configuration and performance details for the M620, based on the
population of the number and type of DIMMs per memory channel.
DIMM DIMM
type 0
SR
DR
UDIMM SR
SR
DR
SR
DR
QR
RDIMM SR
SR
DR
QR
20 PowerEdge M620 Technical Guide
on Dell.com/Support/Manuals.
Table 8. Memory speed capabilities
Number
DIMM DIMM
1 2 of DIMMs
SR
DR
DR
SR
DR
DR
SR
800* 1066*
1 ∞ ∞
1 ∞ ∞
2 ∞ ∞
2 ∞ ∞
2 ∞ ∞
1 ∞ ∞
1 ∞ ∞
1 ∞ ∞
2 ∞ ∞
2 ∞ ∞
2 ∞ ∞
2 ∞ ∞
Dell PowerEdge M620
Speed (MT/s)
1333 1600
∞ ∞
∞ ∞
∞ ∞
∞ ∞
∞ ∞
∞ ∞
∞ ∞
∞
∞ ∞
∞ ∞
∞ ∞
1866
∞
∞