Dell PowerEdge M820 Systems Owner's Manual

Memory bus operating frequency can be either 800 MT/s, 1066 MT/s , 1333 MT/s, or 1600 MT/s depending on the:

• DIMM type (RDIMM or LRDIMM)
• DIMM configuration (number of ranks)
• Maximum frequency of the DIMMs
• Number of DIMMs populated per channel
• DIMM operating voltage
• System profile selected (for example, Performance Optimized, Custom, or Dense Configuration Optimized)
• Maximum supported DIMM frequency of the processors

The system contains 48 memory sockets split into four sets of 12 sockets, one set per processor. Each 12-socket set is organized into four channels. In each channel, the release levers of the first socket are marked white, the second socket black, and the third socket green.

Figure 1. Memory Socket Locations

Memory channels are organized as follows:

Processor 1

channel 0: memory sockets A1, A5, and A9

channel 1: memory sockets A2, A6, and A10

channel 2: memory sockets A3, A7, and A11

channel 3: memory sockets A4, A8, and A12

Processor 2

channel 0: memory sockets B1, B5, and B9

channel 1: memory sockets B2, B6, and B10

channel 2: memory sockets B3, B7, and B11

channel 3: memory sockets B4, B8, and B12

Processor 3

channel 0: memory sockets C1, C5, and C9

channel 1: memory sockets C2, C6, and C10

channel 2: memory sockets C3, C7, and C11

channel 3: memory sockets C4, C8, and C12

Processor 4

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

The following table shows the memory populations and operating frequencies for the supported configurations.