What are all the parts of my computer?
Ian Waugh masters the acronyms and delves into the anatomy of a modern PC
This is an update to a feature we ran, ohhhh, ages ago and it's amazing to see by how much computers have progressed. Many "standards" have become obsolete as newer and faster technology has been adopted. However, the main parts of a PC system are essentially the same; only the names, designs, speed and capacity have changed!
- Cooling system
- CPU (Central Processing Unit)
- OS (Operating System)
- Graphics card
- Hard drive
- Optical drive
- Sound system
- PSU (Power Supply Unit)
The case, obviously, houses the PC's innards. There are three main case types - desktop, mini tower and full tower.
A desktop case is rectangular a little like a VCR (remember those?) and users would often place the monitor on top. However, they are now generally out vogue in favour of upright or tower cases although many Media Centre PCs are desktop in design. One of the main drawbacks of the desktop is that they can be cramped inside which limits the amount of expansion cards they can hold.
The majority of modern PC cases are tower systems and stand upright. Many people put them on the floor under the desk although some cases are smart enough to stand on top of the desk and be considered furniture!
Smaller cases - often called mini towers - can't hold as much as larger models, naturally. This may not be an issue if you're sure you won't want to expand your PC but such cases may not allow you to add additional disk drives or plug-in large expansion cards, for example, especially the latest generation of graphics cards which can struggle to fit inside a normal tower case. So you need to check a case's capacity if you're planning to add upgrades.
The motherboard in a tower case is usually mounted vertically on one side giving you easy access to components. If you enjoy upgrading or want to build your own PC, you'll want a tower case. But be aware that they are not all created equal by any means. Apart from internal capacity, they vary enormously in what components they come with (fans and so on) and in aesthetics.
You've probably noticed that your PC gets hot. All those electronic components can generate a terrific amount of heat and need to be kept cool to avoid becoming unstable and crashing your system.
Cooling is traditionally provided by fans and most cases include a fan or several as standard. The PSU will usually have its own fan as will the CPU on the motherboard. In some high-end PCs it's not unusual to see half a dozen fans.
All these fans invariably produce a degree of noise so if you work in a quiet environment you may want to pay careful attention this. There are low-noise fans available (for a few dollars more) and they can be a most worthwhile investment.
Another form of cooling system has come to the fore in high-end and high-speced PCS - water! This is generally used with systems that are overclocked to make them run faster than their specs say they can. Overclocking means they run faster and hotter and need more efficient cooling systems to keep them stable. Water cooling systems look cool - sorry! - making a PC look like the innards of a Cyberman! It's wonderful techy stuff.
The name says it all - the Mother and the heart of the PC. This is the large circuit board in the middle of the case which houses the main components of the computer. These include the BIOS (Basic Input/Output System that determines what the computer can do without accessing programs from a disk), the cache and, of course, the CPU. Interestingly, some high-spec motherboards are starting to appear with built-in water cooling systems.
There will be slots for plugging-in memory (RAM) and expansion slots for plugging in devices such as graphics cards, TV Tuners and so on. Also connections for various controllers which will vary from board to board. Older boards had a range of serial and parallel ports but, as we said at the start, technology is moving on and the current ports of choice include USB, FireWire, EIDE (for older drive connections), SATA (for modern drive connections, possibly eSATA (for external drive connections), PCI and PCI-E (for graphics cards), keyboard (PS/2) and mouse connections (although some boards omit a dedicated mouse port in favour of USB).
There will usually also be an Ethernet LAN (Local Area Network) port or two and often a modem and a WiFi port. Most motherboards also have built-in sound capabilities, many of good quality, although musicians and dedicated audiophiles will inevitably want to add a dedicated sound card.
Motherboards are quite complex although, in spite of having an increasing number of features, they are arguably easier to work with than motherboards of several years ago.
It's reassuring to know that most of us don't need to know exactly what they contain or how they work. Any complete computer system you buy ought to be optimally set up so the motherboard and all its bits are working together in perfect harmony.
However, if you intend to customise, change or add anything to the motherboard, read the manual carefully. Keep it safe. Final words of wisdom - don't mess with the Mother unless you're know what you're doin'!
The processor or CPU controls the computer. This is The Man (or Person if you insist on being politically correct). This is the brains. This does the business and makes your computer run. Essentially it executes instructions and transports data round the computer system. Fast is definitely better!
CPUs have names, too. If you're young you may not remember the 386 or the 486 but Pentium chips are still around. These are all Intel products and the latest chips are the Core 2 series which comprise the Duo, Quad and Extreme. Most current PCs of reasonable spec will host a Core 2 Duo.
AMD CPUs are the prime alternative to Intel chips. Over the years, the two companies battled it out leapfrogging over each other with new developments, but Intel's Core 2 has currently gained the edge in price and performance. AMD's Barcelona Quad Core might give Intel a run for its money but we'll have to see.
The OS is what makes then PC, er, operate. Windows is the most popular OS ever and we're now seeing a transition, albeit it slowly, from Windows XP to Vista. Microsoft says it's "retiring" XP in 2008 although it will continue to support the product for some time to come.
But there are alternatives. Linux is the most popular alternative OS for the PC - it's also free! - and Apple Macs have their own Mac OS, currently Version X.
Software applications such as word processors, spreadsheets and games, have to be written for a specific operating system so, alas, you cannot run a Windows game under Linux. However, there are many, many free Linux applications should you want to explore that OS, although there are a great deal more free programs for Windows, too.
Graphics cards are also known as video cards or video adapters and they're responsible for putting the images generated by the computer onto a monitor.
The display can be in a range of resolutions. Common ones are 800 x 600, 1024 x 768, 1280 x 1024, 1680 x 1050 and higher, but there are other resolutions, too. The display can use a range of colours from 16 or 256 right up to 16-bit, 24-bit or 32-bit which supports millions of colours. The greater the resolution and the more colours the card displays, the more memory it requires and the longer it will take to draw the image.
Originally, graphics cards simply plugged into a PC's expansion slot but in order to deliver more power, dedicated graphics connectors were developed. Until recently, the port of choice was the AGP (Advanced Graphics Port) designed as a replacement for PCI, but this has now been replaced by the PCI-Express 16x (known as PEG). Some motherboards have two PEG slots allowing two cards to drive two monitors, and multi-card configurations for die-hard gamers.
For programs which require high-resolution graphics that change quickly such as games, you need a powerful video card. In fact, if you're a games player you will certainly want a high-end card.
For less strenuous applications such as wordprocessing and surfing, performance is not such an issue. However, applications which rely heavily on the display such as graphics applications and perhaps music applications whose displays need to be updated quickly in real-time will also benefit from a fast graphics card.
The latest high-end video cards are being designed to take advantage of Microsoft's new DirectX 10 graphics technology which renders images and 3D games in greater detail at high resolutions.
But whatever your application, it's a good move to get a fast card rather than a bog standard one as a slow graphics card can cause a bottle neck and slow down the overall performance of your computer.
These are the plugs and sockets on the back on your computer. Once upon a time, the main ports were Serial and Parallel which were used to connect printers and scanners but they have been overtaken in the main by USB. This can be used to connect almost anything to your PC including printers, scanners, a mouse, external hard drives, cameras, music interfaces, modems, routers and so on.
The current slot for plugging in expansion cards is the PCI-E (PCI Express) which is replacing the PCI connector.
Another popular port is FireWire which tends to be used for more demanding applications like digital audio and video cameras but this seems to be slowly losing ground to USB, too.
You'll usually find Ethernet connections round the back, for connecting computers together to create a LAN (Local Area Network).
Other ports you may see are PS2 for connecting a keyboard and mouse.
Port connections are usually built into the motherboard although you can often add additional ports such as USB and FireWire by plugging in an expansion card. Most computers have at least four USB ports. If you want to add a lot of peripheral equipment, it's important that your machine has enough connections although if you're short of USB ports, for example, you can add a USB hub to get more.
The stuff DRAMS are made of. Sorry! Memory is where the computer does its sums, essentially an area where data can be stored, retrieved and manipulated.
Most people call memory RAM which stands for Random Access Memory. It's not a particularly helpful acronym. It simply means that the computer can dive in and access any part of the memory, unlike a tape backup system, for example, where you might have to wade through meters of tape to reach a certain item of data.
RAM is volatile which means that when you remove the power, its contents is lost which is why you are taught from an early age to save often.
To confuse matters, there are several types of RAM and, as technology marches on, even more types are appearing. It's all about being able to shift more and more data with more and more speed.
The two main types of memory are SRAM (Static RAM) and DRAM (Dynamic RAM). SRAM retains its contents for as long as power is supplied to it. DRAM, however, only retains data for a few milliseconds, even under power.
Memory comes in all sorts of shapes and sizes and it's essential to get the correct memory chips for your system. Most current RAM types will be a type of DDR (Double Data Rate) although you may still come across SDRAM (Synchronous DRAM). The acronyms getting to you yet?
DDR2 (wait for it - Double Data Rate Two Synchronous Dynamic Random Access Memory) has been in use since around 2005. Without getting into the technicalities, it runs about twice as fast as DDR and generally needs less power.
The new kid on the block is DDR3 which, as you might imagine, runs even faster (around twice as fast as DDR2) but, as of writing, it's emerging technology, needs a motherboard that specifically supports it and currently it offers little advantage over DDR2. But that should change.
Obviously, the speed of the RAM is important if you want to get the best performance from your PC and, odd though it may sound, the same type of RAM from different companies does not necessarily run at the same rate. And different companies charge different prices for, what appears to be, similar chips.
RAM is one PC component that can be overclocked to increase performance but, as you may guess, not all RAM is capable of being overlocked to the same degree.
Even without overclocking, to get the most from your PC, If you're running Windows XP you should have a minimum of 1Gb RAM and if you're running Vista, 2Gb. Yes, the systems will run with less but it's like having a car with five gears and not getting out of third.
Other types of memory include ROM or Read Only Memory. This is a better acronym and it means that the computer can retrieve data from it but it can't write to it, like a finalised CD. There are lots of ROM chips in a computer, used to store set-up data and information which doesn't need changing. Data in ROM is permanent and remembered after switching off.
Flash memory lets you change its contents and remembers it after switching off. This is popular in modems, for example, cameras and, of course, USB flash drives.
There are also Flash Drives known as SSD (Solid State Drive/Disk) which use a type of memory rather than being a mechanical disk drive. Accessing data from a Flash Drive is faster than from a hard disk - but they are currently significantly more expensive.
The technical description of a hard drive would probably go something like this - a collection of hard platters coated with magnetic material to which data can be written and read using a series of read/write heads.
A drive might have up to eight platters (although the current trend is to use a smaller number of larger platters) which rotate, typically, at speeds of 5420 or 7200 rpm. The whole unit is sealed inside a case which prevents dust getting inside. The heads fly above the platters at a distance of from 10 to 25 millionths of an inch and a speck of dust could cause serious damage.
Hard drives have been getting cheaper and their storage capacity larger over the years. Rare now is the PC which comes with a drive smaller than 80Gb (other than laptops), and 250Gb and 500Gb drives are the norm.
Modern drives connect to the motherboard via a SATA interface. The eSATA interface was designed for adding an external drive and there are also very affordable USB drives if you need additional external storage.
Optical drives read CDs and DVDs. Most computers come equipped with a drive that can both read and write CDs and DVDs and the drives are quite cheap.
The main difference between them is the speed at which a drive writes to a disc, typically 16x although the speed varies depending on the media (CD or DVD).
Most motherboards feature a built-in sound system with audio in and out sockets. For many people this is fine. The quality of on-board sound has improved over the years and you may find it very acceptable for listening to MP3s, video presentations and VOIP calls.
But if you want higher quality, there are a vast number of audio expansion cards available for all types of user from the gamer to the audiophile and the dedicated computer musician.
Lights? Yes, indeed! We mention this for anyone who would enjoy customising their PC. Custom cases often have neat-looking grills and some have translucent sides - add a few lights and your PC looks more futuristic than the most futuristic of PCs!
Lights are likely to be cold cathode fluorescent lights (CCFL) and LEDs. CCFLs are generally blue and green although you can get red(ish) ones. The tubes themselves usually run quite cool but they use an inverter which can become hot so position them with care.
LEDs (Light Emitting Diodes) have been around for donkeys. Popular colours include red, yellow ,blue and green. They don't get hot, are small and can be strategically placed in many interesting corners of your PC's case.
Monitors have come on in leaps and bounds over the past few years, principally thanks to the development of TFT (Thin Film Transistor) screens. In fact, it would be rare now indeed to see a PC bundled with a CRT monitor.
Screen size has also increased with 17" being the current usual smallest size. Many systems now come with a 19" screen with a resolution of 1280 x 1024 and larger screens are becoming increasingly popular. A 22" screen, for example, can typically show a resolution of 1680 x 1050. As TFTs take up less room and are much lighter, bigger screen sizes are easier to accommodate.
Larger screens can run at higher resolutions (see Graphics cards) so you can see more on the screen. However, unlike CRTs which can display a range of resolutions, most TFTs are designed to work at one specific resolution. You may be able to change resolutions but the display will likely not be as sharp.
Another consideration with TFTs is the viewing angle. Move too far away from a "square on" position and the screen may become more difficult to read. This varies from monitor to monitor.
Many TFTs above basic models also have a digital input (which requires that the graphics card has a digital output) which should produce an even sharper image.
Given the smaller size and weight of TFTs, and the fact that prices are still coming down, they are the monitor of choice unless you need crystal sharp displays at more than one resolution.
The PSU drives the whole shebang. It's an oft-forgotten but most important part of the computer. The more gubbins inside the PC, the more power you need to drive it.
Manufacturers are trying to reduce the power consumption of many parts but it's still important to have an efficient PSU to keep the system stable. If you're into overclocking, a quality PSU is a must.
A typical off-the-shelf PC may have a PSU rated at 250W which might be enough to power the computer's current configuration but it may not leave much room for expansion. 350W would be better. A high-end PC could easily use a PSU with a rating of 600W or higher.
Another thing you might want to consider with a PSU is the noise produced by its fan. Some PSUs are quieter than others.
This has been a brief overview of the main parts you'll find inside your PC. New developments are appearing every week. Specific items mentioned here will change - that's guaranteed! - although, as we said at the beginning, the core items that make up a PC are likely to remain the same for quite a while yet.