CPU (Central Processing Unit) Speed:
As you may have noticed even the slowest of processor speeds in today's desktop are far faster than the CPU's found in systems even a few years ago. The processor speed is important because it gives you a basic idea of how fast your system will perform. Of Course you have to realize that the CPU speed is not the be all and end all in determining system performance. Many tasks that a desktop system could be used for are not that dependant on the speed of the CPU. CPU intensive tasks include such things as 3D gaming, audio/video manipulation, animation, 3D graphic design, 2D image manipulation, and intensive mathematical equations. Tasks that aren't as CPU dependant include Internet surfing, Word Processing, e-mail, report creation, financial software, and education.

The speed of the CPU is measured in MegaHertz (Mhz) or GigaHertz (Ghz) a term used to describe how many operations per second the CPU is capable of performing. The CPU speeds that you will encounter in your search for a new computer will range all the way from 500 Mhz up to an astounding 1.5 Ghz. Of course a 1.5 Ghz CPU is strictly for the power user and not for everyday use, unless your everyday use is a lot more CPU intensive than the rest of the worlds.

Amount of RAM (Random Access Memory) :
RAM is a very important part of the computer purchasing equation as basically the more RAM you have the more things you will be able to work on at one time. Another important feature of RAM that the more you have the less your computer will have to access the slower components that are located in your system. Think of RAM as your desktop at work, the larger your desktop is the less often you will have to reach into the filing cabinet in order to work on things. The larger your desktop is the more work you can leave on it at one time.

The average amount of RAM installed on a desktop computer in today's retail market is usually 64 MB. If your needs are strictly business, word processor, or internet surfing then 64 MB will be more than enough. If your into gaming or other high end graphics oriented work than I would recommend 128 MB or more in your new system. More RAM does not means that better performance, it will depends heavily on the operating system, applications, and processor.

CD-ROM (compact disc read-only memory)/ Digital Versatile Disk Read Only Memory (DVDROM) drive/CD-R(W)(compact disk recordable/rewritable) drive :
All personal computers have either a CD-ROM Drive or a DVD-ROM drive installed in them as almost 100 percent of all new software is distributed on CD. Speed is measured in an X rating which signifies how much faster a certain CD-ROM Drive is faster than the very first CD-ROM drives. 1x = 125k/sec transfer rate. For example a 48X CD-ROM is forty eight times faster than a first generation CD-ROM drive. Most systems ship with CD-ROM drives of 24X and faster. Once you get past 24X the difference in speeds between slower drives and the faster ones diminish due to the physical limitations of the media. Even the CD rom is capable of 50X, it might only be operating at 20X.

DVD-ROM drives are an alternative to CD-ROM drives that are capable of reading DVD disks as well as CD-ROM disks. DVD disks are capable of holding many times the amount of data that a CD-ROM disk can. DVD drives can also playback DVD Video Disk with the right software. The speed of DVD is measured also in an X rating, which signifies how much faster a certain drive is compared to the first generation DVD ROM drives. The current speed standard is 4X or higher drives. A 4X DVD- ROM drive is capable of reading CD-ROM disks at a speed equivalent to a 38X CD-ROM drive.If the computer you are looking at includes a DVD- ROM drive and the cost is not prohibitively higher than an equivalent system with only a CD-ROM drive you should purchase the one with DVD in order to enable you to use future software which might only be distributed on DVD. DVD-ROM drive usually cost twice as much compare to CD-ROM drive.

CD-R(W) drives are an alternative to CD-ROM drives that are capable of creating CDs using special CD-R(W). Normal CD-ROM will be able to read these CD-R(W) like normal CDs. CD-R drive will only be able to record once on CD-R while CD-RW drive will be able to record once on CD-R and capable of rewriting on a CD-RW like a floppy disk. These drives are great for creating special audio CDs or backup since the price for a CD-R is only ~US$1 and ~US$5 for a CD-RW. However, these CD-R(W) will not be able to last as long as the normal CDs due to the short life of the dye used on the CD-R(W). Their lifetime will be at least 10 years, which is the best compare to other type of storages.Current standard recording speed will be 4x or higher and rewriting speed is 2x or higher. Most standard CD-R(W) drives are capable of reading at 24X or higher. A 4/2/24X CD-RW drive is capable of recording at 4X, rewriting at 2X, and reading at 24X.

Hard drive:
The hard drive is a very important factor in your purchasing plans because it determines how many programs or applications you can install on your computers. It's interesting to note that if you purchase a small hard drive you could conceivably fill it just by installing your operating system. To most users I would recommend purchasing as large a hard drive as you can reasonably afford. This is recommended because the size of computer programs and applications is constantly increasing at an exponential rate. It's always better to have too much space than to not have enough. 

Most desktop systems ship with hard drives in 6.4 GB in size or higher all the way up to a immense  80 GB. Most home users will end up purchasing a system with a drive around 10 GB to 40GB in size.

Another thing you should keep in consideration is the speed of your hard drive. The speed of the drive is usually determined by its rotational speed. Rotational speed is the number of times per minute the disk spins in a complete circle. The faster this disk spins the faster data can be retrieved from the hard drive.

Most desktop systems ship with drives than spin at either 5400 RPM or 7200 RPM, both are sufficient for most peoples needs but the 7200 RPM drives are noticeably faster and about 20% more expensive for the same capacity. Some high-end systems use SCSI (Small Computer Systems Interface)drives which can spin up to 15000 RPM, of course these systems are designed for the demanding high performance user. Most new hard drive are Ultra ATA/66 or ATA/100 interface(supports transfer rates of up to 100 MB/sec in Ultra DMA Mode-4), however, Ultra ATA/33 hard drives will still be available at bargin prices.

Video Card:
When you purchase your system you have to be aware of the importance of the video card that you get with the system. If you are looking to play games on your new computer than you had better make sure the video card in your system has decent 3D acceleration abilities.

Most current systems ship with Video Cards with at least 8 MB of Video RAM (Video Random Access Memory) which is usually sufficient for the average business user. Those people interested in playing games or partaking in graphics intensive applications should consider video cards with 16 or 32M VRAM.

If you plan on purchasing an LCD flat panel monitor you should consider getting a video card with a digital LCD output connector. Flat Panel LCD screens will operate using a normal monitor output but perform better with the proper connection.

Sound Card:
The sound card is one of the least vital of the major components of a desktop computer since all of the sounds cards currently available are capable of producing decent audio quality. A special sound card may be required if the system is to be heavily used as a gaming machine as sound cards geared towards gamers can produce a "surround" sound effect. Sound cards also exist for those interested in developing professional quality digital audio. What you should be looking for is a 16 bit sound card or anything better. 

Modem/Network Card:
If you are planning on connecting your new desktop system to the Internet you must have either a modem or Network Card in your system. If you plan on connecting to the Internet in the traditional fashion, (i.e. through the standard telephone connection) you will require a Modem. The Modem is a device that allows your computer to send and receive data through a telephone line. The newest modem speed is 56K v.90, which is the current standard. Most modems are capable of sending and receiving fax transmissions. 

If you plan on using one of the new high speed connections such as Cable, or xDSL (Digital Subscriber Line) you will require a network card to interface to these new technologies. The standard network interface for these technologies is called RJ45. Most providers of these new technologies will provide you with the proper interface card so you usually don't have to have one installed in your system when you purchase your system. 

Expansion/Upgrade:
Something that many computer shoppers don't take into consideration is the expandability of the system that they are planning to purchase. This is an important thing to take into consideration as you never know what you might have to add to your system in the future as your needs and desires change. The things you should know when you make your purchase are as follows:

• Number and size of free drive bays: 
• Number and type of free expansion slots: 
• Power Capacity of the power Supply:
• Motherboard expension capability of faster/future processor