Dell PowerEdge R430 Owner's Manual page 58

Figure 17. System memory board
Memory channels are organized as follows:
Processor 1 channel 0: memory sockets A1 and A5
channel 1: memory sockets A2 and A6
channel 2: memory sockets A3 and A7
channel 3: memory sockets A4 and A8
Processor 2 channel 0: memory sockets B1
channel 1: memory sockets B2
channel 2: memory sockets B3
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