
Dell EMC PowerEdge M640 Installation and Service Manual
System memory guidelines
The system supports DDR4 registered DIMMs (RDIMMs) and load reduced DIMMs (LRDIMMs). System memory holds the instructions that are executed by the processor.
Memory bus operating frequency can be 2666 MT/s, 2400 MT/s, or 2133 MT/s depending on the following factors:
- DIMM type (RDIMM or LRDIMM)
- System profile selected (for example, Performance Optimized, or Custom [can be run at high speed or lower])
- Maximum supported DIMM frequency of the processors
The PowerEdge M640 system contains 16 memory sockets split into two sets of 8 sockets, one set per processor. Each 8-socket set is organized into six channels. In each channel, the release tabs of the first three sockets are marked white, and the fourth socket black.
Memory channels are organized as follows:
| Processor | Channel 0 | Channel 1 | Channel 2 | Channel 3 | Channel 4 | Channel 5 |
|---|---|---|---|---|---|---|
| Processor 1 | Slots A1 and A7 | Slots A2 | Slots A3 | Slots A4 and A8 | Slots A5 | Slots A6 |
| Processor 2 | Slots B1 and B7 | Slots B2 | Slots B3 | Slots B4 and B8 | Slots B5 | Slots B6 |
