The motherboard, also sometimes referred to as the main board, is a collection of devices (together on one large circuit board) that control the flow of data and operating electricity for all the primary components in a PC - for example, the CPU, memory, graphics adapter and sound card.
Socket A/754/939 - These motherboards support socket A, 754 or 939 processors which are generally found in much older systems. These boards generally have IDE connections onboard for connecting components and will run DDR1 memory.
Socket AM2 - These motherboards are the most common and will support any AM2/AM2+ socket processor. These boards generally support DDR2 memory and have mainly SATA connections with minimal IDEs onboard.
Socket AM3 - AM3 motherboards are the newest revision and will support the higher end processor. Thee motherboards generally support DDR2 or DDR3 memory and have mainly SATA connections with minimal IDEs onboard.
Socket FM1 - AMDs latest, the FM1 socket motherboard supports DDR3 memory and mainly SATA sockets to deliver performance. While most motherboards require both a CPU and graphics card, the FM1 socket supports AMDs Fusion processor which not only allows for great processing power but also feeatures high end graphics on the chip itself!