System Memory - Dell EMC PowerEdge R940 Installation And Service Manual

Figure 50. Cable routing – 24 x 2.5 inch hard drive backplane with NVMe cards
1 24 x 2.5 inch hard drive backplane with expander board
3 PCIe cable
5 system board
7 NVMe card (slot 8)
9 NVMe card (slot 12)
11 PCIe cable
13 cable management bracket (right)

System memory

The system supports DDR4 registered DIMMs (RDIMMs) and load reduced DIMMs (LRDIMMs). System memory holds the instructions
that are executed by the processor.
NOTE: MT/s indicates DIMM speed in MegaTransfers per second.
Memory bus operating frequency can be 2667 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 R940 system (without PEM) contains 24 memory sockets split into two sets of 12 sockets, one set per processor. Each
12-socket set is organized into six channels. In each channel, the release tabs of the first socket are marked white, and the second socket
black.
The PowerEdge R940 system (with PEM) contains 48 memory sockets split into four sets of 12 sockets, one set per processor. Each 12-
socket set is organized into six channels. In each channel, the release tabs of the first socket are marked white, and the second socket
black.
2 backplane power cable A
4 backplane signal cable
6 expansion card riser (left)
8 expansion card riser (right)
10 NVMe card (slot 11)
12 PCIe cable
14 backplane power cable B
Installing and removing system components 95