For many people, the motherboard is a somewhat mysterious system component. All too often, people choose a motherboard based primarily upon price in the belief that all motherboards are essentially alike. This perception is understandable, given the fact that the motherboard appears to provide no real functionality - it doesn't store data, it doesn't do calculations and it doesn't display or print. In fact, all the motherboard appears to do is provide the communication channels between all of the various devices that actually do the real work.
The motherboard is actually a very important part of your system, and has a great impact on the overall system performance. Every device in your system needs to communicate with a controller that transfers data to and from system memory where the processor can access it. This includes hard drives, floppy drives, CD-ROMs, printers, mice, keyboards, monitors… the list is long. There is also a controller that coordinates the transfer of data between the processor, cache and main memory. These controllers determine to a large degree the reliability, compatibility and performance of your entire system, with the majority of them residing on the motherboard itself.
In addition to the controller circuitry, most of the other components on the motherboard are either sockets, plugs and pins for connecting devices, cables and wires or are devices that provide timing signals or regulate the power to the various connectors. These include the processor connector, the expansion card slots and memory slots. These are all discussed in more detail later.
Far too many users have found out that the bargain motherboard they purchased has cost them more in grief and time spent diagnosing and recovering from problems than they would have saved even if the board was free. This is not to say that the motherboard should be picked first, and all other components chosen around it. What it means is that at least as much consideration should be put into choosing your motherboard as in choosing the processor or video card - perhaps even more.