Dell EMC PowerEdge R740 Installation And Service Manual page 102

Figure 56. Memory socket locations
Memory channels are organized as follows:
Table 41. Memory channels
Processor Channel 0
Processor 1 Slots A1 and A7
Processor 2 Slots B1 and B7
102 Installing and removing system components
Channel 1 Channel 2
Slots A2 and A8 Slots A3 and A9
Slots B2 and B8 Slots B3 and B9
Channel 3 Channel 4
Slots A4 and A10 Slots A5 and A11
Slots B4 and B10 Slots B5 and B11
Channel 5
Slots A6 and A12
Slots B6 and B12