Dell PowerEdge M830 Owner's Manual page 48

Figure 10. 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
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