General Memory Module Installation Guidelines - Dell PowerEdge M820 Owner's Manual

Processor 4
The following table shows the memory populations and operating frequencies for the supported configurations.
DIMM Type DIMMs Populated/
Channel
RDIMM 1
2
3
LRDIMM 1
2
3

General Memory Module Installation Guidelines

This system supports Flexible Memory Configuration, enabling the system to be configured and run in any valid chipset
architectural configuration. The following are the recommended guidelines for best performance:
• RDIMMs and LRDIMMs must not be mixed.
• x4 and x8 DRAM based DIMMs can be mixed. For more information, see Mode-Specific Guidelines.
• Up to two quad-rank RDIMMs and up to three dual- or single-rank RDIMMs can be populated per channel.
• Up to three LRDIMMs can be populated regardless of rank count.
• Populate DIMM sockets only if a processor is installed. For dual-processor systems, sockets A1 to A12 and B1 to
B12 are available. For four-processor systems, sockets A1 to A12, B1 to B12, C1 to C12, and D1 to D12 are
available.
• Populate the sockets by highest rank count in the following order - first in sockets with white release levers,
then black, and then green. For example, to mix quad-rank and dual-rank DIMMs, populate quad-rank DIMMs in
the sockets with white release tabs and dual-rank DIMMs in the sockets with black release tabs.
• In a dual- or four-processor configuration, the memory configuration for each processor must be identical. For
example, if you populate socket A1 for processor 1, then you must populate socket B1 for processor 2, and so
on.
• Memory modules of different sizes can be mixed provided that other memory population rules are followed (for
example, 2 GB and 4 GB memory modules can be mixed).
• Populate four DIMMs per processor (one DIMM per channel) at a time to maximize performance.
• If memory modules with different speeds are installed, they operate at the speed of the slowest installed
memory module(s) or slower depending on system DIMM configuration.
channel 2: memory sockets C3, C7, and C11
channel 3: memory sockets C4, C8, and C12
channel 0: memory sockets D1, D5, and D9
channel 1: memory sockets D2, D6, and D10
channel 2: memory sockets D3, D7, and D11
channel 3: memory sockets D4, D8, and D12
Operating Frequency (in MT/s)
1.5 V
1600, 1333, 1066, and
800
1333, 1066, and 800
1600, 1333, 1066, and
800
1066 and 800
1333, 1066, and 800
1333 and 1066
1333 and 1066
1066
1.35 V
1333, 1066, and 800
1066 and 800
1333, 1066, and 800
1066 and 800
1066 and 800
1333 and 1066
1333 and 1066
1066
Maximum DIMM Rank/
Channel
Dual rank
Quad rank
Dual rank
Quad rank
Dual rank
Quad rank
Quad rank
Quad rank
53