The Motherboard
When you open up a computer case you see a large printed circuit board underneath all the other components. This circuit board is the motherboard. The function of the motherboard is to provide power and connections to all the other components of the computer.
The motherboard (or mobo as it is sometimes called) has various sockets for inserting other cards such as video cards or audio cards. It also has a socket for the Central Processor Unit (CPU), and this socket determines what kind of CPU can be used in the motherboard.
CPU Socket
Motherboards are usually classified by their CPU socket. When shopping for a motherboard you will see Socket A, Socket 478, or Socket 775 for example. The different types of sockets use different pin layouts for accepting the CPU. You cannot fit a Socket A CPU into a Socket 478 motherboard.
When you see a name like Socket 478 or Socket 939, the number refers to the number of contacts that the CPU has. Socket A (also called Socket 462) was the most popular type of layout for AMD processors until recently. It is gradually being replaced by Socket 754 and Socket 939.
Socket 478 is a common layout for Intel processors such as the Pentium 4. Intel is gradually introducing a new socket layout called Socket T (also called Socket 775 or LGA 775).
Chipsets
Chipsets are the intermediary between the CPU and the other components of the computer. Chipsets are divided into two parts -- the Northbridge and the Southbridge. The Northbridge is the faster of the two. It connects directly to the CPU through the Front Side Bus (FSB). The Northbridge also connects directly to the memory and the AGP graphics slot.
The Southbridge connects to the PCI cards, the USB ports and the hard drive. Information from the CPU must first pass through the Northbridge to the Southbridge and finally to the external components.
Unlike CPUs, chipsets cannot be removed from the motherboard. It is important to consider the chipset when buying a CPU/motherboard combination. CPUs are optimized for certain chipsets, so you should choose a motherboard with a chipset that complements the CPU.
Buses
All aboard! Computer data needs a way to travel from one component to another. Like many people, data takes a bus. Buses connect the various parts of the motherboard to the CPU through the chipset. The speed of the bus determines how fast data can reach the CPU.
Bus speed is measured in megahertz (MHz) and is an important factor in computer performance. The Front Side Bus (FSB) connects the CPU to the Northbridge so the speed of this bus is a very important specification of any motherboard. There is a broad range of bus speeds on current motherboards -- from about 200 MHz all away up to 1600 MHz.
Memory Slots
Most motherboards will have two or three slots for memory chips, but some have up to seven memory slots. The slots are designed to accept memory modules with a certain number of pins. It is important to buy the correct type of memory module for your motherboard.
Modern motherboards are designed to accept Double Data Rate (DDR) memory, which is twice as fast as regular memory because it can be accessed on both the up and down cycles of the CPU. DDR2 is even faster than DDR, and is quickly becoming the standard for computer memory.
If you are in the market for a new motherboard, there are several things you need to consider to make a good choice. If you wish to use your existing CPU, you are limited to buying a motherboard that accepts that type of CPU. However, if you wish to upgrade both the motherboard and the CPU, you have many more options.
There are two routes -- choosing a motherboard to match a specific CPU, or choosing a CPU to match a specific motherboard. Deciding how the computer will be used will determine which combination of CPU and motherboard you should buy.
Most computer programs will operate without problems on almost any combination of motherboard and CPU. It is only when you are using the computer for special applications like CAD, video editing, multitrack music recording, or games that you need to pay special attention to choosing a motherboard.
Games are some of the most CPU intensive applications around. The latest games rely on state-of-the-art processors and video cards to show off their maximum potential. Video editing also requires a lot of processing power especially when using a lot of transition effects. CAD (Computer Aided Design) and audio editing are number three in requirements for computer power.
Each of these applications has different requirements for add-on cards. High-end video cards are required for both games and video editing, but are not so important for audio work or CAD. Sound cards are not necessary for CAD but are needed for the other three types of applications. Sound recording is not important for gaming but is needed for both video and audio work.
Expansion Slots
Motherboards have expansion slots to accept other cards like video cards and audio cards. Most motherboards will have four or five PCI (Peripheral Component Interconnect) slots for accepting add-on cards like network adapters, modems, audio cards, or extra USB slots. In addition, there should be an AGP (Accelerated Graphics Port) slot for a 3-D graphics card.
PCI slots have a bus speed of 33 MHz and AGP slots are rated at 66 MHz. Both of these are set to be replaced by a new standard -- PCI Express.
Other Connections
Other things that can be installed in the computer case are the hard drive, the CD or DVD drive and the floppy disk drive. These are usually connected through the IDE interface, although some motherboards also support other types of drives such as SCSI or SATA. It is important to know the type of interface on the motherboard when buying hard drives and CD-ROM drives.
A final consideration when buying a motherboard is the form factor. This is the size and layout of the motherboard and determines the kind of case that is needed. Form factors also determine the number of slots that can be added to the motherboard.
There is a huge selection of motherboards on the market today. The price range is from less than R600 to over R3000. Before choosing which motherboard to buy, you must seriously consider how the computer is going to be used. Processor intensive applications like CAD and some computer games require top-of-the-line components. Computers that will be used for browsing the net and word processing do not need as much power.