Computer Hardware Knowledge !  ( by Saahir )

TV Card
 

A TV card gives you the option of watching TV on your monitor. TV cards are quite useful as it offers more than just watching TV. You can connect your VCR to the TV card so that you can watch video's too. One of the useful things about having a TV card is that you can use it for capturing Video. Using the necessary software you can capture video in various format such AVI or MPEG files. One of the popular TV card is Haupauge WinTV PCI as shown below.

Older TV cards were all analogue device. Now you can get Digital TV cards which allows you to view Digital terrestrial TV channels. You can even get Digital Satellite and Cable TV cards.

Motherboard
 

A motherboard is a Printed Circuit Board (PCB) that connects your processor, memory and all your expansion cards together to assemble a PC. Most motherboards made nowadays are ATX. An ATX motherboard has the standard I/O (Input/Output) connectors such as PS/2 ports, USB ports, parallel port, serial port, etc, built onto the motherboard. ATX motherboard fits into a standard ATX case. The following is a picture of a Modern ATX motherboard.

As you can see from the image, the motherboard comes with various expansion card slots and connectors. It comes with 4 different expansion slots, 2 PCI and 2 PCI Express slot. 

The PCI slot is where you would connect cards such as sound card, modem, tv card etc.

The PCI Express slot is where you would connect a PCI-E graphics card. This particular motherboard allows to have two different graphics cards in a SLI or Crossfire configuration.

The other connectors includes Intel LGA 1366 Socket, DDR3 Memory slots, ATX 2.0 24pin power connector. SATA connector for connecting your Hard drive, DVD-ROM etc.

 Memory - DDR2 DDR3 SDRAM
 

Memory is the name given to silicon chips that stores volatile computer data. Volatile means that the contents of memory will be lost if the power of the computer is switched off. Memory stores some of your operating system and application data while it is being run. The more memory you have in your system, the more application you can run simultaneously and will provide an overall better system performance.

Memory comes in many form. The older systems use SDRAM, while the current systems use DDR2 or DDR3 SDRAM (Double Data Rate Synchronous Dynamic Random Access Memory).

Depending on the motherboard you choose you need to select the matching compatible memory. For example if you buy an Intel motherboard for an Intel Core 2 Duo CPU then it will support Dual-channel DDR2 800, 667 or 533. Therefore you can buy any DDR2 memory at those speeds. However DDR2-800 memory will run the CPU bus at the optimal speed while slower memory are backward compatible. It is recommended that you get the highest memory speed your motherboard supports if you want the maximum performance. If you are on a budget then slower speed memory would be sufficient. Please note, DDR-2 memory must be run in pairs to run at double data rate. So if you decide to get 2GB of memory then you need to buy 2 x 1GB modules. It is also best to get both pairs of memory from the same manufacturer to avoid incompatibility.

Most AMD Athlon 64 X2 and Phenom processors also support DDR-2 at speeds mentioned above.

If you have the latest Intel i7 motherboard then you will need a triple-channel DDR3 1600, 1333, or 1066. 

It is always best to ask your retailer or check the manufactures website to make sure that your chosen memory is compatible with your chosen motherboard. Some of the well known memory manufactures are Crucial, Kingston, Corsair, and Samsung. The following list shows all the current types of DDR2 and DDR3 memory.

DDR2 Memory:Memory name I/O Bus Speed Module name
DDR2-400 200 MHz PC2-3200
DDR2-533 266 MHz PC2-4200
DDR2-667 333 MHz PC2-5300
DDR2-800 400 MHz PC2-6400
DDR2-1066 533 MHz PC2-8500


DDR3 Memory:Memory name I/O Bus speed Module name
DDR3-800 400 MHz PC3-6400
DDR3-1066 533 MHz PC3-8500
DDR3-1333 667 MHz PC3-10600
DDR3-1600 800 MHz PC3-12800

Hard Disk Drive
 
Hard disk drive stores all your data including operating system, applications, user files and documents. It is a non-volatile storage, which means the contents of the HDD is not lost if the PC is switched off. 

There are three different types of HDD, which are IDE/ATA, SCSI, SATA (Serial ATA). Majority of home PCs are equipped with IDE Hard drives. SCSI hard drives are mostly included in servers and powerful workstations as they offer better data transfer rate which results in better performance than the IDE drives. However modern SATA drives are not far behind SCSI drives in terms of performance with the introduction of the newer SATA 300 drives. 

The price of IDE/SATA drives have fallen quite dramatically in the recent years. You can buy a very large drive for a competitive price. It is better to buy a drive which is quite large as it works out cheaper. A recommended entry level drive would be 80 GB to 120 GB. The major HDD manufacturers are IBM, Seagate, Maxtor, Western Digital and Fujitsu. For our demonstration PC I have chosen use an IBM ATA100 drive as shown below.

Processor (CPU)
 
The processor also known as CPU (Central Processing Unit) is the brain of a computer. The faster the processor, the faster it will execute instructions and run your programs. The leading Processor manufactures are Intel and AMD. Whichever manufacturer you decide to choose you will have to make sure that you purchase a compatible motherboard. 

Nowadays Intel and AMD have stopped the GHz race and concentrated on how many cores they can fit in each CPU. So having a 3 GHz single core CPU is not better that having 2.4 GHz Dual Core CPU. Nowadays a CPU is judged on how many cores it has. The more cores it has the better it is.

Before buying your processor consider what the system is going to be used for. If you are going to use your system for word-processing, browsing the web or other basic tasks, it may be sufficient for you to use an Intel Celeron, AMD Sempron or an AMD Athlon 64 processor, which are available at a very competitive price. 

If the system is going to be used for spreadsheet, databases, graphics and playing some moderate video games then you should consider an Intel Core 2 Duo or an AMD Athlon 64 X2 processor. 

Intel Core 2 Duo and Athlon 64 X2 are both Dual Core. Which means they have two CPU cores in one Chip. Each core works separately hence the CPU can process two intensive tasks at the same time without slowing down the system. For example you might be running a virus checker in the background while playing games without slowing your system down. They are also 64 Bit and support 64 bit Operating System. 

If the system is going to be used as an advanced workstation for doing work such as Video Editing, CAD, or playing the latest 3D video games or other CPU intensive tasks then you will need a higher end quad-core or multi-core processor such as AMD Phenom X4, Intel Core 2 Quad or Intel i7.

AMD Phenom X4 and Intel Core 2 Quad has four cores. Intel i7 has 4 cores but each core can process two threads so your operating system will treat it as 8 different processor. All of these modern processors are 64 bit which means they can execute 64 bit instructions and run 64 bit operating systems. They are all very fast and are capable of handling most of your computing needs.

Monitor / LCD Display
 

It is important that you get a quality monitor that is comfortable to view. Monitors come is various sizes and refresh rate. 17" monitor are becoming entry standard monitor. 15" monitors are OK if you are running it at a low resolution and not using it for long hours. As monitor prices have dropped in the recent months it is recommended that you consider a 17" or 19" monitor. You can run these monitors at higher resolution and refresh rate, which means they are more comfortable to view and you can work with them for long hours. Monitors are measured diagonally. If a monitor is 17" it does not mean that it is the actual viewable area. Some 17" comes with a viewable area of 16" which is good where as others can be as low as 15.6". Monitors consist of thousands of pixels (the tiny dots you see on the screen). Smaller pixels produces high definition sharp display. Settle for something which is at least 0.25 mm dot pitch. If you purchase a 17" monitor make sure it can handle refresh rate of at least 85 Hz at 1024 * 768 resolution. A 19" monitor should handle at least 1280 * 1024 at 85 Hz.

Currently the most popular viewing device are TFT Flat panels. They are now more affordable than before. Most people prefer TFT Flat panels as they save lot of desk space. They are also more comfortable view

CD or DVD-ROM
 

Nearly all operating systems and applications software comes on CD. It is therefore essential to have a CD-ROM drive for installing your applications. Certain programs requires the CD to be in the CD-ROM drive for that program to run. For example, various encyclopedia and games. CD-ROM can also be used for playing standard audio CD's on your PC. 

If you are intending to watch DVD movies on your PC then you would require a DVD-ROM which can perform all the tasks of a CD-ROM as well as play DVD movies. 

CD-ROM's come in various speeds, the faster drive, the faster it will install your applications. DVD drives specifies two types of speeds, one for the software installation and other for the DVD extraction. For example a DVD drive with 16x32x specification means that it is a 16 speed DVD and 32 speed CD. Some of the CD/DVD-ROM manufacturers include Toshiba, Poineer, Hitachi, LG and Samsung.

Desktop or Tower Case
 

A desktop or tower case is required to hold all your components together. It is your personal preference on which one you decide to choose. Desktop or tower cases come in standard ATX form factor. You can find them in many different design & sizes. The most common sizes are Mini, Midi and Full tower. Most budget cases come with PSU (Power Supply Unit) but most of the premium cases don't come with PSU which has to be purchased separately. The case below is an ATX Midi Tower case.

To decide if you need a mini, midi, or a full tower case you need to ask yourself how many hard drives, dvd-rom etc you need to fit in the case. The bigger the case, the more bays you will have for your drives and peripherals. If you are building a pc which has to be small as possible and you are planning to buy a Micro ATX Motherboard then go for a Mini Tower case.

Note, if the case is really small and cramped then it will have less air flow, which means the case temperature would be higher than having a larger case with good air flow. This could lead to an unstable PC.

Sound Card
 

If you require sound for your PC then you will need a sound card. As basic sound cards are very cheap it is recommended that you consider a sound card. It offers many benefits such as running multimedia applications with sound, listening to wave, midi, and MP3 music files or even play your audio CD's. If you are thinking of playing games on your PC then having a sound card is a must. Most current motherboards also have basic built in sound. One of the most popular sound cards are the Creative's soundblaster range. We will use a Creatives Sounblaster Live 1024 for our demonstration PC as shown below.

Modem
 
Modem stands for Modulator Demodulator. It converts digital signals to analogue so that it can travel via your telephone line, and vice-versa. A modem is an essential item if you are intending to connect your PC to the internet. 

There are many kinds modems out there based on the Rockwell/Connexant v.90/v.92 chipset. There are two kinds of modem, software and hardware. Software modems uses your CPU resources to perform its tasks and is run on a virtual COM port. Hardware modem performs its tasks using the onboard chipset and therefore does not take up the CPU resources. It also runs on a physical COM i.e. communication port 3. Software modems, which are also known as winmodem can only run on a windows operating system, while the hardware based modem can run on other operating systems like linux. External modems are mostly hardware based and connect to the serial port. You can also get external modems that connect to the USB port, however most of these are software based.

Analogue modems are currently on the decline as they are being replaced by Digital modems which are used for high speed broadband internet. Also known as ADSL modem or ADSL routers. ADSL modems are mostly external although you can get Internal ADSL modem's. Many people are also using Wireless ADSL routers as it offers an excellent way to share internet connections with multiple PCs. Some common ADSL Router suppliers are Netgear, Belkin and D-Link. 

I have decided to use a Connexant 56K v.90 software modem for our demonstration PC as it performs quite well in terms of download.