What processors are compatible with the AM3 motherboards?
AM3 compatible processors are from the AMD FX, AMD Phenom II, Athlon II, and Sempron series of CPUs. CPUs compatible with the AM3 socket are no longer in production, but are still available for purchase as refurbished processors.
The AM3+ Socket is slightly different in that it has one extra pin. AM3 processors can be installed into an AM3+ socket, but not the other way around. Processors compatible with the AM3+ are from the FX and Opteron series, along with those mentioned above.
Is AM3+ backward compatible with AM3?
AM3+ processors have an extra pin compared to AM3 processors, making them incompatible with the AM3 Socket. Some AM3 motherboard were revised and released with an updated socket to allow for this compatibility, but as a rule, AM3+ processors will not work in an AM3 socket.
Are Socket am3+ motherboards compatible with DDR2 RAM?
AM3+ motherboards & CPUs are not compatible with DDR2 RAM (they have native DDR3 controllers built into the processor), but because some AM3+ boards also backwards support AM3, you may find a few rare AM3+ boards with both DDR2 and DDR3 slots. In this unusual configuration you can install DDR2 memory along with an AM3 CPU into an AM3+ motherboard.