Buying a Computer

The motherboard

The motherboard tends to be overlooked when purchasing new individual components or a PC package as a whole. Most people first check the processor and its clock speed, then the size of the hard drive, and perhaps check which graphics controller is lurking inside. Considering the motherboard is essentially the backbone of your PC, attention should be paid to this component as it will shape the longevity of your PC system.

If you're unsure what a motherboard looks like, a quick peek inside your PC will set you straight. It will invariably be the biggest single item in there. It not only plays home to your processor and memory, but all your expansion cards: your graphics card, your hard drive and CD-ROM connectors, plus external ports. The motherboard also houses the BIOS (Basic Input/Output System) that controls the simplest configuration of your machine.

The BIOS also performs the POST (Power on Self Test) health check when you switch on your machine. This is a diagnostic testing sequence that begins as the PCs power is turned on. If the components are configured correctly, the PC will continue booting into the operating system.

Motherboards for AMD and Intel

A motherboard, in almost all circumstances, will only support one type of processor, such as Intel's Pentium 4, or AMD's Athlon64. Different chips have connectors that vary physically from one another. It ensures that you can't plug the wrong chip into the wrong board by accident.

The motherboard chipset

The second way in which motherboards differ is in the chipset they use. If you think of the motherboard as the physical hardware, the chipset is the logic that underlies it. It is the part that dictates how different components actually talk to one another and controls the features and abilities of the motherboard.

Processor development and chipset design go hand in hand - so much so that the chipset is built to support the facilities offered by a certain processor. There are a number of chipset vendors on the market, with the five main companies being Intel, AMD, VIA, NVIDIA and SiS. Intel and AMD only produce chipsets for their own processors, while VIA, NVIDIA and SiS make chipsets for both companies.

Chipset manufacturers have produced a large range of chipsets, based on a variety of north bridge and south bridge types. The most recent, and most advanced, releases for Intel processors are the Intel 945/955X chipset (which support the dual-core processors), the NVIDIA nForce4, the SiS655 and the Via PT894.

For AMD motherboards, look for recent chipsets including the NVIDIA nForce4, the SiS761 and the Via K8T890.

Below, we've included a list of many chipsets you might see appear in motherboards now. (November 2005)

Motherboard slots

Although some motherboards support different features, several key components are present on all current models. Each will be designed to take either a socket or contact-based processor and there will be memory module slots for either DDR SDRAM or DDR2 SDRAM. There will also be expansion slots so you can add extras like sound and graphics cards; support for the hard and DVD+/-RW drives; and, finally, connectors for keyboard, mouse and peripherals.

Motherboards with built-in sound and graphics

It's also quite common for motherboards to have some built-in basic sound or graphic capabilities. Take note: integrated graphics obviate the need for a separate graphics card but generally offer poor 3D games performance in comparison. This is because integrated graphics use system RAM to run, which takes away from overall system performance.

Integrated audio, on the other hand, is often quite good, with some sound chips handling digital output for up to 8 channels.

If you only want to use office applications, then an onboard graphics chip should suffice; die-hard gamers, on the other hand, should install a dedicated card.

Interfaces

Universal Serial Bus

Universal Serial Bus (USB) is a standard for connecting peripheral devices to a computer. It was designed to replace PS/2, serial and parallel connections (which still appear in many motherboards).Low-power USB devices can sometimes be directly powered from the PCs power source via the USB connection, but only when the device draws less than 5v. You would expect to see at least 4 USB ports on the rear faceplate of a motherboard but latest release motherboards have up to 6 ports, with two located on the front of the case.

Firewire

IEEE 1394, which is commonly referred to as FireWire (but also as i.Link by Sony), is used to connect devices such as digital video cameras to your personal computer at a speed of 400Mbps. FireWire supports up to 63 devices on a single bus.

A newer version of FireWire is referred to as IEEE 1394b. The architecture of the new specification technically supports speeds up to 3.2Gbps, but initial implementations only work at 800Mbps. However, the biggest change for FireWire may not be the doubling of speed, but the range provided by the specification. The current version of FireWire works at a distance of 12-15 metres. The 'b' spec will increases that distance up to 115 metres.

S/PDIF (Sony/Philips Digital Interface)

Developed jointly by the Sony and Phillips corporations, S/PDIF allows the transfer of digital audio signals from one device to another without having to be converted first to an analog format.

Headphones

A port for a 3.2mm audio jack, usually green, used to connect external headphones. Usually located on the motherboard, some PC cases may have a pass-thru cable with an additional connection on the front.

Microphones

Similar to the headphone jack, this is a (usually pink) 3.2mm audio port to connect external microphones. Pass thru cables are also used here for connection at the front of the PC.

Line in

A connection that is used to input an audio signal into your PC. For example, you can connect your stereo's CD player to it and listen to it through your PC. Simply connect an audio lead from your CD player through to the sound card and output the audio to a set of 5.1 speakers connected to your PC.

Parallel

A 25-pin data transfer port used predominantly for connecting printers. Although the USB ports are increasingly used.

Serial

Game controllers and older-style dial-up modems would normally use this type of 9-pin connection.

PS/2

Typically used for connecting a mouse and keyboard. Easy to identify, these 6-pin ports are often coloured green for mice, purple for keyboard.

© LEV