M61PME-S2P has only two memory sockets (like almost all value motherboards). As the memory controller is inside processor, the memory type you can install depends on the CPU. Socket AM2 processors accept up to DDR2-800 memory, while AM2+ processors support up to DDR2-1066 modules, in both cases supporting dual channel configuration. You can install up to 8 GB of memory, with two modules of 4 GB.

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Figure 3: Memory Sockets.