Overview Of Motherboards

I have written this guide to help you understand how a computer motherboard works and the various functions it controls inside of the computer tower


Just like the central processing unit is the brains behind any computer system, the motherboard (also known as mainboard or system board), is the central nervous system. In one way or another, the motherboard is responsible for the flow of information between every device inside of the computer. The motherboard determines what hardware can be added to the system in the future, as well as where everything should be fitted inside of the case. Motherboards also dictate how fast information can travel through components inside the computer tower. More specifically, the motherboard determines what type and speed of processor can be used, and how fast that processor can communicate with other components inside the system.

Motherboards are comprised of various elements including serial and parallel communication ports, memory and processor placeholders, hard disk drive and floppy disk drive connection pins in addition to a variety of tiny microchips (referred to as chipsets) which control the functions of devices soldered into the motherboard's design.

Motherboards range in size, color, and capabilities, but the principles behind them remain the same. The motherboard is used to control the flow of data between all peripheral devices within the system. A peripheral device is a type of computer part that you cannot physically see; a mouse, keyboard, and computer monitor is considered a non-peripheral device, whereas a hard disk drive, memory stick, and processor fan are considered peripheral devices because they are invisible inside of the computer's tower.

Integrated Vs. Non-Integrated Motherboard Designs

Characteristics Of An Integrated Motherboard

More modernly designed motherboards have devices integrated onboard including video display adapters, sound cards, and networking devices such as modems and network controllers. These types of motherboards can be referred to as integrated boards since a variety of components usually included as separate expansion cards are integrated within the motherboard design itself, often resulting in a more inexpensive board. These types of boards are commonly found in a variety of small form factor based computers; proprietary companies such as Dell and HP use integrated boards to limit the upgradability of a system.

In addition to sound and networking controllers, motherboard manufacturer's will design a motherboard with the graphics controller onboard, often sharing the memory with regular system memory. These video cards are less powerful than a regular video card which plugs into a dedicated expansion slot, and are often very unappealing to a power user or a hardcore gamer.

Integrated motherboards don't have adequate room for expansion. As a result, these styles of motherboards are best suited for budget based computers, or shuttle style PC's. Office environments typically use workstations comprised of integrated motherboards because cost wise they are far cheaper to implement.

Characteristics Of A Non-Integrated Motherboard

Non integrated motherboards are more expensive than their counterparts since there is more room for expansion within these types of designs. On a good non-integrated motherboard design there's room for at least five Peripheral Component Interconnect (PCI) based expansion cards and the board always includes an Accelerated Graphics Port (AGP) for connecting a PC's video system. The majority of newly designed motherboards that utilize a non-integrated design are equipped with a PCI-Express slot for the display system, completely overhauling the design of the AGP interface. PCI-Express is the newest generation for expansion busses and as a result the fastest type of bus available.

Incidentally, onboard devices are a invaluable way to free up expansion slots yet are typically not as powerful or feature rich as other separate expansion based cards are designed. Onboard devices soldered into a motherboard directly require additional chipset's and controlled through the operating system. For example, a motherboard with on board video and sound cards require separate chipset's to control the functioning of both devices. A chipset is a series of controller chips on a motherboard that contain pre-programmed logic that determine how the device functions. The hardware interacts with the chipset and operating system components.

A more expensive and generally better motherboard design does not include on-board devices, but does include a more than average number of PCI based expansion slots in addition to PCI-Express slots.

Motherboard Form Factors

In the computing world the term form factor refers to the architecture of a motherboard. Form factor is referring to the style or shape that the motherboard conforms to in the computer. This architecture encompasses several factors including the dimensions of the particular board and the type of power supply unit (PSU) required for properly powering all devices the motherboard controls.

At present day, there are currently three types of motherboard designs incorporated into full systems. They are:

1. ATX Form Factor;
2. Micro ATX Form Factor, or Mini ATX;
3. Small Form Factor.
   

Other obsolete styles of motherboards include:

1. Baby AT and
2. AT
   

Motherboards that use an ATX form factor are comprised of Pentium II, III, or IV based micro processors.  They also require the use of SDRAM memory modules. Some ATX boards use DDR-SDRAM memory, the next generation SDRAM memory technology. The obsolete motherboard form factors used SIMM technologies, one generation lower than most SDRAM technologies.

The list below shows an at-a-glance look at the various form factors past and present.

Baby AT

• Old and obsolete computer hardware.
• Did set the standard for future AT based motherboards.
• Designed for 8088, 80286, 80386, and 80486 based computers.

AT

• Old and obsolete computer hardware.
• Designed for Pentium I and II based computers.

ATX

• Most popular motherboard style.
• Best used in either a desktop or tower based PC.

Micro ATX

• Mini version of the ATX.
• Best Used in "shuttle" and media center style PCs.

Factors To Consider When Purchasing A Motherboard

Purchasing a new motherboard or replacing an exisitng one doesn't have to be a difficult procedure provided that you know what type of setup you currently own.

1. How old is your existing computer?

Depending on the age of your existing computer, you will want to decide whether an upgrade is feasible. If your motherboard is limited to a Pentium III processor or slower sometimes purchasing an entirely new box (e.g. tower or desktop) equipped with a modern processor is a better way to go. You can always reuse the existing parts such as sound and network cards, but you will need to purchase new memory and a better processor to upgrade to the latest PC standards.

2. Are you replacing a defective motherboard or upgrading because you need more computing power?

If you are replacing a defective motherboard then you will more than likely need to replace the processor and memory as well.

If you are looking to add extra functionality to your existing setup, you'll want to look for a motherboard that provides added bells and whistles such as SATA, RAID, and Firewire connectors. Older motherboards can accommodate separate expansion cards that support these features, but it may be more economical to upgrade to an entirely new motherboard design that has these features built in.

3. How much are you looking to spend on the replacement?

You will need to figure out how much you can afford to spend on the replacement. If your existing PC is comprised of older parts, you're better off to invest more money and get more modern parts.

4. What type of memory and processor is in your current system?

If you have an older PC chances are the memory and processor are outdated. If this is the case, you will need to figure out what motherboards are compatible with the memory and processor you currently own. It's important to note that the older SDRAM memory is not compatible with modern memory modules such as DDR and DDR2 RAM. If your looking to reuse existing parts ensure you know exactly what type of motherboard you need to purchase.