Introduction

Your PC (Personal Computer) is a system, consisting of many components. Some of those components, like Windows XP, and all your other programs, are software. The stuff you can actually see and touch is hardware.

Hardware

The hardware are the parts of computer itself including the Central Processing Unit (CPU) and related microchips and micro-circuitry, keyboards, monitors,case and drives (hard, CD, DVD, floppy, optical, tape, etc...).

Other extra parts called peripheral components or devices include mouse, printers, modems,scanners, digital cameras and cards (sound, colour, video) etc...

The devices which are Necessary to assemble a computer

•  Motherboard

•  Processor

•  Memory

•  Hard Drive

•  Video Card (if motherboard didn't come with it)

•  Sound Card (if motherboard didn't come with it)

•  Modem and/or Network Card

•  Floppy Drive

•  CD-Rom

•  Keyboard and Mouse

•  Case And Power Supply

•  Monitor

Processor

The Central Processing Unit, Which is often referred to as the "Processor" is the brain of the computer. The chip that performs the majority of calculations and instructions needed to make your computer run. Without this chip, no other function of the PC is possible. The processor is attached to the motherboard (Processor slot).

The speed of the CPU

The computer's speed or clock rate is integral to its overall design. The computers clock rate is the frequency at which it can execute a set of instructions. Computer clock rates are measured in Megahertz (million of clock ticks per second).

There are two types of speeds that should be considered when evaluating the system performance:

Internal clock speed - Is the speed at which the processor can obtain information within itself, like with internal cache and registers. (Pentium III 800 MHz. the 800 MHz is the internal clock speed)

External clock speed - Is the speed at which the CPU communicates with components outside itself.

Some commercially available processors

. Pentium I-IV

. Celeron

. Athlon

. Duron

. Cyrix C3

. Itanium (64 bit)

. Opteron (64 bit)

How to Choose a CPU

When you are choosing one CPU always consider your computing needs when selecting a CPU. If you want to do simple word processing or general computer tasks, go for the budget or low end processors. If you are more into gaming or do CPU intensive work like video editing, go for a mid-range or high-end processor.

Motherboard The motherboard is the main circuit board inside your PC. Every components at some point communicates through the motherboard, either by directly plugging into it or by communicating through one of the motherboards ports. The motherboard is one big communication highway. Its purpose inside your PC is to provide a platform for all the other components and peripherals to talk to each other. Modern motherboards come with the following features: Processor slot : Processor slot is used for processor. Memory banks : Memory banks are used for RAM modules. AGP slot : AGP slots are used for graphics accelerators. PCI slots : PCI slots are used to provide connectivity for PCI cards such as modems and sound cards. IDE : IDE are used to connect and control IDE devices such as hard drives and CD-ROM drives. USB ports : USB ports are used to connect USB devices. These are just some of the features that a motherboard may have as standard, some motherboards come with integrated components such as a sound card, graphics card, modem, NIC (Network Interface Card) and more. Types of Motherboards The type of motherboards depends on the CPU it was designed for. You can therefore categories motherboards by which socket type they have. e.g. Socket A, Socket 478 etc. The Type of motherboard you buy is very important, as it will need to house your CPU, and they are not interchangeable. When buying a motherboard, it will always tell you what socket type it has. How to Choose a Motherboard As everything you have on the PC at some point needs the motherboard, you need to consider these components when buying a motherboard. For example, if you have a lot of devices with a PCI interface that you wish to use, there is little point buying a motherboard that only offers you 3 PCI slots. Like wise with memory, you have to make sure that there are enough slots for the amount of memory you have or wish to have. The motherboard also needs the correct type of interface for your Memory, Graphics card, Hard disks and other items as well. You will find that most motherboards offer everything you need however it needs checking on when buying. Its especially important to pay detail to your motherboard if you want to use older components, which a new motherboard may or may not support. The major difference between motherboards that support the same CPU is the model of the chipset (more on the chipset later). Different chipsets offer different performance and different features in terms of memory support, AGP port speed, Multiplier numbers, Bus speeds and much more. When you are choosing one motherboard you have to consider: What's Your Processor? First and most important thing to consider when buying your motherboard - what CPU or processor are you using? Motherboards are made differently, not all motherboards will support all CPUs. What CPU you select will determine the type of motherboard you get. For example, if you want to use an Intel Pentium 4 CPU, the motherboard you select must be able to support that brand and model of CPU. The motherboards are also designed to support specific speeds for a CPU, so make sure it can support the speed of the processor as well. Choose Your Chipset What is a chipset? Well, chipsets are the main controllers on the motherboard - they allow the CPU to interface with the various components and expansion cards installed. When choosing your chipset, always bear in mind the type of memory supported by the motherboard. Make sure that the board supports the type and amount of RAM you need. Generally, choosing a chipset that supports high speed memory will allow your system to perform better.   What is a Motherboard Chipset? A motherboard chipset controls all the data that flows through the data channels (buses) of the motherboard. The primary function of the motherboard chipset is to direct this data to the correct area's of the motherboard, and therefore the correct components. Expansions Slots and Connectors If you intend to various peripherals to the computer, then the number and type of expansion slots and connectors is important. By default, most motherboards these days have USB 2.0 ports incorporated into their design. If you intend to buy expansion cards, make sure the board comes with an ample number of PCI slots. Other Features These days, most motherboards have a whole host of extra features loaded into them. These can include things such as on-board VGA, audio, a RAID controller, Modem or Network Card. RAM RAM (Random Access Memory) is the basic working memory of your computer system. A computer used RAM to hold volatile (Temporary) instructions and data needed for processing. Volatile simply means that it is not permanent, which means anything written to RAM will be loses if the machine loses power or if it's turned off. Another key point about RAM is that data stored init can be accessed much more quickly than data retrieved from the hard disk. Theoretically data retrieved from RAM is accessed 100 to 300 times faster then the same information from a hard disk, optical drive, or a floppy. Memory is measured in bytes, so you'll often encounter the terms megabyte (MB) and gigabyte (GB) in describing RAM sizes (a megabyte is a million bytes; a gigabyte, a billion). RAM is something that you do not want to skimp on. You can choose a slower processor, but with RAM you want as much as you can get.   Types of RAM: SDRAM DDR DDR2 DDR3 1. SDRAM Almost all systems used to ship with 3.3 volt, 168-pin SDRAM DIMMs. SDRAM is not an extension of older EDO DRAM but a new type of DRAM altogether. SDRAM started out running at 66 MHz, while older fast page mode DRAM and EDO max out at 50 MHz. SDRAM is able to scale to 133 MHz (PC133) officially, and unofficially up to 180MHz or higher. As processors get faster, new generations of memory such as DDR and RDRAM are required to get proper performance. 2. DDR Memory   (184-pin DIMMS) These were introduced in 2002 to replace the earlier SDRAM format. To use this type of memory you need a 184-pin socket for the module to fit into. DDR Memory is available in different speeds of PC2100, PC2700, PC3200 (DDR400), and PC4000 (DDR500). The modules can be used singly or how desired however you cannot mix different speeds together. 3. DDR2 Memory   (240-pin DIMMS). This format builds on the technology of   DDR . This standard has more pins and its main developments are the ability to run faster whilst consuming less power. To use DDR2 memory you need a 240-pin socket for the module to slot on your motherboard. DDR2 Memory is available in many different speeds including PC2-3200 (DDR2400), PC2-4200 (DDR2533), and PC2-5300 (DDR-667).   The modules can be used singly or you can install different speeds of DDR2 memory together if your motherboard supports the faster speed however faster modules will perform at the lower speed. This may be worth considering if you want to run Dual-Channel memory where you must use the same speed and ideally matching pairs to ensure compatibility. 4. DDR3 Memory   (240-pins) THIS is the latest memory standard (2008 onwards) taking over from the previous   DDR  and DDR2   standards. Although DDR3 comes with 240-pins the same as DDR2 the notch is in a different place so people can not install the wrong type. DDR3 is not backward compatible with DDR2 in addition to the notch the voltage runs at a lower 1.5V than DDR2 1.8V. DDR3 memory will not fit into a standard DDR2 DIMM socket or an earlier DDR memory socket. To use DDR3 memory, your system motherboard must have 240-pin DIMM slots and a DDR3-enabled chipset. HardDisk The hard disk (or hard drive) is the permanent storage area of your computer. It stores information whether the computer is on or off. A hard drive is a mass storage device found in all PCs (with some exclusions) that is used to store permanent data such as the operating system, programs and user files. The data on hard drives can be erased and/or overwritten, the hard drive is classed as a non-volatile storage device which means it doesn't require a constant power supply in order to retain the information stored on it (unlike RAM). Inside every hard drive are small round disk-like objects made of either an aluminum/alloy or a glass/ceramic composite, these are called platters, each platter is coated with a special magnetic coating enabling them to store data magnetically. Hovering above these platters are read/write heads that transfer data to and from the platters. Hard drives come with many different storage capacities, hard drive capacity is measured in bytes, with common capacities being stated in MB (Megabytes) and GB (Gigabytes). Hard Drive RPM Speeds You will often see hard drives advertised as being capable of a certain RPM (Revolutions Per Minute), this figure (as the name suggests) refers to how many times the spindle makes a complete 360? turn in any single minute. RPM values range from about 5,400RPM to 12,000RPM and above. How to Choose a Hard Drive When you are choosi ng one Hard Drive you have to consider: ATA and SCSI In the hard drive world, there are two data access standards, ATA and SCSI (pronounced 'Scar-Zee'). Most of normal hard drives we're used to rely on the PATA standard. Some newer hard drives use the SATA standard. SATA allows transfer speeds of up to 150 MBs while PATA gives up to 133 MBs. However, to use SATA, you'll need a Serial ATA controller, a SATA drive and a SATA power cable. The speed difference between PATA and SATA is also not significant unless you have a high-end SATA drive. The SCSI standard is a very fast hard drive standard used for professional computer systems which demand extremely fast data access. SCSI drives provide an access time of about 9.5ms - which I feel is really not needed for average home use. Disk Space vs. Price An important factor to consider is the disk space versus price ratio. When you look at the 30 GB, 40 GB and 80 GBPATA hard drives, you'll find they are very close in price. For the average home user, however, 40 GB to 80 GB of disk space is plenty. Drive Speed If data access speed is important to you, you can go for faster SATA drives or SCSI drives. But remember that these drives come at a price premium and may not be necessary for average home use. Video Card VGA Card is the one sending the monitor signal to the monitor. A computer video card is placed in the motherboard, where it transfers video signals through a cable to your monitor. The video card can either be built into the motherboard or be a separate card that is placed in either the AGP or PCI-Express Slot. The computer graphics cards major job in a computer is to convert graphic patterns into signals for the monitor's screen. However in recent times as the graphics card has become more advanced it has taken some of the jobs previously assigned with the CPU and through a graphics pipeline adds 2D and 3D effects and it also adds textures. How to Choose a Video Card The VGA Card price will change on VGA Card Processor VGA Card Ram capacity Ram type of VGA Card When you are choosi ng one Video Card you have to consider: The best way to see what video card to buy is to consider how you're using your computer now. There are several categories: Server If you're using your computer as a mail server, FTP server, print server, or even a game server, you definitely do not need a high-end video card. What you need is a simple, no-frills low-end video card. Simple Applications Say you're using the PC for simple applications only, for example, word processing, email or web surfing. Again, you do not need the best video card out there. A cheap and decent one will do the trick. Complex Applications If you need to perform more complex tasks like 3D computer aided design or video editing, it will make more sense to go for a heavy duty card. Screen resolution and image quality tend to be important factors for this type of work. Look for a video card whose processor which supports a high screen resolution, with ample graphics memory. General Games If you'll only play simple games like Minesweeper, Reverse or Backgammon, then my advice is to save your money and just get a simple video card. No need for the latest 3D graphics gizmo.  Sound Card The sound card is an essential component in the PC, since it translates digital signals into analog audio for your listening pleasure. Well, that's true, if you want to play games or run multimedia applications in your PC. Otherwise, it may not be necessary, especially in business environments. Sound card ports A computer sound card is used by a computer for music, sounds during applications and entertainment (TV, movies and games). A typical sound card usually has four ports. The largest port is the Midi/Game port , which is used for connecting a joystick or gaming controller to. The other three ports look similar and are generally green, pink and blue. Underneath each port will be a small engraving of what each port does. The pink port is for a microphone which can record sound to the computer. The green port is line out and this is where the speakers are connected to produce sound from the computer. Theblue port is line in and this is for connecting a CD-player or cassette tape to the computer. Remember a sound card by itself is not enough to hear sound. You will still need to purchase some computer speakers or a headphone set. If you want to make use of the microphone feature then you will need to buy a computer microphone and you should then be able to record sound to your computer. How to Choose a Sound Card When you are choosi ng one Sound Card you have to consider: First thing to consider here is your intended usage of the sound card. If all you want is basic sound support and not spectacular 3D surround sound, I'd say go buy a cheap, simple card or even rely on your motherboard's on-board sound. If you want great surround sound and better speaker connectivity options, then you'll want to consider a dedicated sound card. Modem Card A device that translates data from your PC into a form that can be sent to other computers over regular phone lines. The modem also receives signals from other computers and converts it into something your computer can understand. A modem is the device most home computers use to connect to the Internet. A Modem converts digital information into sound so that it may be transmitted over telephone lines. When the modem hears this sound on the other end it converts the sound back into digital information. There are two types of modems: •  INTERNAL •  EXTERNAL External modems are slightly more expensive than internal modems and are housed in an external box or enclosure. External modems require a socket on the computer or port (usually the serial port on the back of your computer.) The serial port is also called a COM port, com for communications. Network Card A   network   interface   card , more commonly referred to as a NIC, is a device that allows computers to be joined together in a LAN, or local area   network. Networked computers communicate with each other using a given protocol or agreed-upon language for transmitting data packets between the different machines, known as   nodes . The   network   interface   card   acts as the liaison for the machine to both send and receive data on the LAN. The most common language or protocol for LANs is Ethernet, sometimes referred to as IEEE 802.3. A lesser-used protocol is Token Ring. When building a LAN, a network interface card must be installed in each computer on the network and all NICs in the network must be of the same architecture. For example, all must either be Ethernet cards, Token Ring cards, or an alternate technology. An Ethernet network interface card is installed in an available slot inside the computer. The NIC assigns a unique address called a MAC (media access control) to the machine. The MACs on the network are used to direct traffic between the computers. The back plate of the network interface card features a port that looks similar to a phone jack, but is slightly larger. This port accommodates an Ethernet cable, which resembles a thicker version of a standard telephone line. Ethernet cable must run from each network interface card to a central hub or switch. The hub or switch acts like a relay, passing information between computers using the MAC addresses and allowing resources like printers and scanners to be shared along with data. A network interface card does not have to be hard wired with physical cable. Wireless Ethernet cards are installed like their wired counterparts, but rather than a port for an Ethernet cable, the card features a small antenna. The card communicates with the central wireless switch or hub via radio waves. Wireless LANs may have some restrictions depending on the material the building is made from. For example, lead in walls can block signals between the network interface card and hub or switch. When buying components for a LAN, make sure the NICs and hub or switch have the same capabilities. The entire network must be either wired or wireless, so a wireless network interface card cannot talk to a wired switch or hub. In addition, newer versions of hardware will likely support more features and/or greater speeds than older versions. Make sure your central switch or hub can utilize the highest capabilities of the network interface card under consideration. Keyboard and Mouse These two input devices are obviously needed, otherwise you can't interact with the computer system. These components are fairly standard stuff and can be purchased at pretty cheap prices. Keyboards The keyboard is the main input device for most computers. There are many sets of keys on a typical “windows” keyboard. On the left side of the keyboard are regular alphanumeric and punctuation keys similar to those on a typewriter. These are used to input textual information to the PC. A numeric keypad on the right is similar to that of an adding machine or calculator. Keys that are used for cursor control and navigation are located in the middle. Keys that are used for special functions are located along the top of the keyboard and along the bottom section of the alphanumeric keys. Keyboards are mainly divided into two types 1. Multimedia keyboard. 2. Ordinary Keyboard. Mouse Mouse is another input device used in computer. Mouse is a device that controls the movement of the cursor or pointer on a display screen. A mouse is a small object you can roll along a hard, flat surface. Its name is derived from its shape, which looks a bit like a mouse, its connecting wire that one can imagine to be the mouse's tail, and the fact that one must make it scurry along a surface. As you move the mouse, the pointer on the display screen moves in the same direction. Mouse contain at least one button and sometimes as many as three, which have different functions depending on what program is running. Some newer mouse also includes a scroll wheel for scrolling through long documents. Floppy Drive A 3.5" square holding a flexible magnetic disc that holds information or data. You need a floppy drive to read the floppy. A floppy disk can hold only 1.44 megabytes, but it is portable and allows you to make copies of your files. CD-Rom A CD-ROM drive used to be an 'optional extra' in computers - it is no longer so. Most software packages come in CD format, so you must have a CD-ROM drive to read them. Typically, CD-ROM drives today need to be at least 24X speed to keep up with the newer software applications out there. A CD drive connects to the computer motherboard through two types of cables. The older and more common connection is through the IDE Ribbon cable . Recently SATA (Serial ATA) drives have been produced and will gradually become more common. The benefits of having SATA cables is that they are smaller and the transfer rate is higher. Floppy drives were the main source of data transfer and files were small enough to fit on them. However, today even CD drives are getting out of date and are fast being replaced by the DVD ROM and DVD RW Drives. CD-RW CD writer is used to write CD. It can also used as a CD drive. CD can be able to write with different formats. By using CD writer we can able to write with different speeds. There are different types of writers are available in the market with different writing speeds. On a CD drive there is usually some numbers with a x symbol after it. This stands for times, for example common speeds are 4x, 8x, 16x, 18x, 24x, 32x, 40x and 52x. CD RW drives have speeds like 24x-10x-40x or 52x-32x-52x. How to Choose a CD-RW When you are choosi ng one CD-RW you have to consider: Drive Speed For CD writers, you should generally look for a 40X record speed or faster. If you buy anything that is slower, it will definitely waste a lot of time when you're burning CDs. Monitor Monitor is the display device. Many times per second, the video card sends signals out to the monitor. The information video card sends controls which dots are lit up and how bright they are, which determines the picture you see. Color monitors can display anywhere from 16 to over 1 million different colors. Color monitors are sometimes called RGB monitors because they accept three separate signals -- red, green, and blue. The resolution of a monitor indicates how densely packed the pixels are. In general, the more pixels (often expressed in dots per inch), the sharper the image. Most modern monitors can display 1024 by 768 pixels, the SVGA standard. Some high-end models can display 1280 by 1024, or even 1600 by 1200. How to Choose a Monitor If you're a graphics professional, you may prefer a CRT monitor because they are said to show more realistic colors. However, the latest high-end LCDs can also give equal color quality. If you with text most of the time, a LCD is a good choice because the various pixels that you find on a LCD will have nicely defined edges. This gives sharp and focus letters on the screen. Computer Case The computer case is your computer's housing. You need this to store your components, the largest of which is your motherboard. Types of Case Mini Tower : Advantages: Excellent size which can be placed on top ofbelow of a computer desk. Disadvantages: While this case does offer upgradeability it can be filled up much faster then the Mid-Sized tower. Recommendations: Great PC for end-users and small businesses. Mid-Size Tower: Advantages: Excellent case which can fit below and on top of your computer desk. Plenty of expandability for new devices for businesses, end-users, and advanced users. One of the most used computer cases found today. Disadvantages: None Full-Size Tower Advantages: Excellent computer for upgradeability. Excellent case for a server machine. Disadvantages: Cost is going to be a lot more then a standard case. Generally A large case which cannot be placed on top or beneath a desk. Recommendations: This case is an excellent choice for all users and businesses. Desktop Advantages: Excellent desk computer. Great use of desk space when monitor is placed on top of the computer. Disadvantages: With some types of desktop cases can be very difficult to upgrade. Does not really work on the floor. Recommendations: We recommend that this type of case be purchased by advanced users or users who plan to have a stand alone machine as a server. How to Choose a Case Choosing a computer case can be difficult if you don't know what your looking for. The range of computer cases is huge and bigger then its ever been. So how do you find one that suits you. This guide will explain how to choose a computer case that suits your needs. What's your budget The first step in choosing a computer case is working out how much you are willing to spend on a case. If you would like to save money then don't spend a fortune on your case. However, if you do buy a decent case then it will be unnecessary to upgrade for a long time. I would say that your case should cost about 5%-10% of your entire budget. So if you are willing to spend $AU1000 on your computer, then spend from $50-$100 on your case. What's your needs The second step in choosing a computer case is making sure that it has enough room to house all your components. If you have two CD drives then get a case that has room for the three drives. Put one at the top and one at the bottom leaving space in between for cooling. Do the same for your hard drives and floppy drives. Also make sure that your motherboard can fit inside the case. Some cases are smaller then others and some motherboards are bigger then others so make sure your motherboard will fit. Next make sure that there is at least one fan built into the case. I would recommend two fans at least and if you are really worried about your equipment over-heating then get another fan. I have a friend who is very worried about over-heating. He has about 6 fans inside his computer and when he turns it on it sounds like an airplane taking off and all the lights in his house go dim. So if your prepared for a little more noise then its a good idea to get an extra fan to cool your equipment down. However, don't get paranoid about fans, one or two should be fine and unless there is no circulation your hardware should survive. Computer Case Style The last thing to do in choosing a computer case, is to choose what you want the case to look like. Do you want a black or white case, a fancy or plain case. The range of computer cases on the market is huge so select one that you like. If you would prefer a cheap computer case then choose a plain one. Many computer cases come with extras at the front like USB and ports for a headset. These can be very useful and are worth it for the extra money. When you are choosing one Case you have to consider: External Space The first factor to consider is how much space your PC case is going to take up. Are you placing it on a tight, crammed desk? Or on a large desk? If you have the space, tower PC cases are a good choice. If you're short of space, you may wish to consider smaller mini PC cases which are getting more popular these days. Internal Space Another factor to consider is how many components you wish to fit in your PC case. If you're a computer nut like me, you'll want to fit in a good motherboard, CPU, a couple of hard drives, video card, LAN card, cooling fans, a CD-ROM drive and a DVD writer. That's a lot of components to be cramming into a PC case! Again, a good choice would be a tower PC case. However, with so many components, you have to watch out for overheating problems - make sure you deck out the system with a couple of good fans. Motherboard Support Check that your motherboard can fit into the case! Some cases are flexible enough to support AT, ATX and Baby-AT boards, but others only support one of these sizes. Even then, you need to be careful - some cheaper 'ATX' cases don't really fit ATX motherboards. I remember buying a wonderful ATX motherboard and it couldn't fit into my PC case! Imagine my frustration!   Power Supply Most PC cases come with power supplies. With more and more components being fitted into a PC, you will certainly need enough juice to power them. Cooling If you're a over clocker or have many system components, you'll need to ensure you've got enough fans in that case to cool the system. Good PC cases allow multiple (4 or more) cooling fans to be installed, ensuring good ventilation.   Looks Just a few years back, PC cases were boring white boxes. These days, you can find a plethora of colorful PC cases - if you're concerned about your PC's 'look'. Many PC enthusiasts I know go for good looking PC cases that come in a variety of colors - red, black, green, blue and what not.  Power Supply A computer power supply is a compulsory unit to a computer. Without the power supply a computer is useless as it is just a case full of metal and plastic. This page will explain the different power cables and connectors and how they work inside your computer. A power cable connects from the power point to the power supply where it supply's the motherboard and other components with power. Often there is a power switch on the back which can be switched off to stop the power current. If this is not switched off and even though the computer is off power will still be drawn out of the power point (very small amount). The most common power supply that we have in our computers today are the ATX Power Supply. The AT Power Supply was found in many computers a few years ago but this has become less common. The graphic below shows each power cable and its name. The computer power supply is placed inside the computer case generally near the top of the case. It is sometimes necessary to buy a mini power supply for some cases are so small that they need one. Most computer cases when bought come with a power supply that is suited to its case. There are usually power ports on the motherboard for the fans in the case but if not it is possible to buy an adapter that will convert power from the 4-pin power cable to a fan power cable.