Basics Dual In-Line Memory Modules (DIMMs) - 34

Power Macintosh/Performa 5400 Series

DRAM DIMMs can be installed individually. However, to take
advantage of the computer’s interleaving capability (which
provides maximum performance), you must install the
DIMMs in matching pairs. Memory interleaving allows the
computer to read or write to its memory while other
memory reads or writes are occurring, providing faster
performance.

Note:

DIMMs purchased from different manufacturers can
be paired as long as they are the same size and speed.