Tips for Buying a Computer
Vince Ory
Baton Rouge General Medical Center, Medical Library, Baton Rouge, LA
What do I buy?
Computer technology is in a constant state of evolution. If you are in the market for a new PC, you may quickly become confused by the cryptic terminology and frustrated with the number of options from which to choose. Several factors influence speed and power. Making an educated choice will require that you become familiar with some basic concepts and answer some basic consumer questions.
- How complex are my tasks? Surfing the Internet requires less computing power than running a multimedia program. If you know the types of programs you will be using, check out their requirements. Most programs state optimum computing capacity on the box labeling.
- Do you require portability? A "notebook" computer may be preferable to a "desktop" computer. Today's notebooks are generally just as fast and powerful as a desktop but have physical size limitations. As notebooks are frequently utilized without external power sources, "on board battery capacity" is an important factor in notebook selection.
- Do you prefer to buy your unit locally or mail order? This is an important choice, for it often dictates what kind of product support you will receive. Do you prefer to take your unit to a local dealer for service or are you comfortable with telephone technical support? Most large manufacturers offer factory direct orders. This allows you to choose from a variety of component specifications rather than settle for what a local vendor happens to have in stock.
- How much can I afford? If your computing needs outstrip your resources, be aware many large manufacturers offer late model factory refurbished machines or closed product lines with variable warranties. Factor in the cost of any extended warranty you may desire. Again, the operational requirements will influence power and options you need. Most systems easily accept memory, video, sound, modem and storage space upgrades. A quality electrical surge protector is a must.
Deciphering the language
The computer utilizes many complex components. Unless you build a machine from scratch, you have little choice over some specifications. While a discussion on each component could fill a chapter, this page covers basic component selections you are likely to encounter. Let's take a look at specifications from a typical advertisement and break it down.
"Computer package includes: Pentium 4 processor at 2.40GHz with 533mhz system bus and 512K L2 Cache, 256 MB RDRAM, 16x Max. DVD-ROM drive, 40GB Ultra ATA Hard Drive (7200 RPM), 128Mb DDR graphics card, 17" (16.0"v.i.s.) dot pitch 0.26 mm monitor, 4 PCI Slots, 1 AGP Slot, 4 USB ports, Front audio jack. 56k modem"
Pentium 4 processor at 2.4GHz with 533mhz system bus and 512K L2 Cache
Processor (AKA: central processing unit, CPU, microchip, microprocessor or chipset) The CPU handles the computer's complex computations. CPU speed (clock speed) is measured in the number of cycles per second executed measured in "hertz" (megahertz/millions or gigahertz/billions). Some processors have performance improving temporary storage areas located within them, known as "Level 1 Cache" (L1) and "Level 2 Cache" (L2). Economy priced processors often lack the L2 cache. Currently 512 kilobytes of Level 2 (L2) Cache is common. The most common processors are the: Pentium II, Pentium III, Pentium IV, Celeron, Duron, and Athlon. At 1.0 to 3.0 GHz. Components inside the computer transmit data to each other via circuit paths (bus) on the main circuit board (motherboard) The width of the data path and the speed at which data moves along these paths dictates the systems BUS Speed. The faster the system bus speed the faster the computer will finish a task.
256 MB RDRAM
Random Access Memory (AKA: RAM, memory, memory chips, or temporary memory) Random Access Memory functions as a temporary data storage area for use by the CPU. RAM memory is housed in series microchips and generally speaking more RAM memory means faster computing. RAM memory is measured in units called bytes. (Megabytes/millions or Gigabytes/billions). Most systems allow you to easily upgrade RAM memory. Currently 128 to 512 megabyte offerings are common in SD RAM or the faster more expensive RD RAM.
40GB Ultra ATA Hard Drive (7200 RPM)
Hard Drive (AKA memory) the hard drive is a magnetically sensitive disc(s) that serves as a permanent storage area for data and programs. Like RAM memory hard drive storage capacity is measured in bytes. Be aware of the size of the programs you will be using and estimate your base hard drive requirements. Most system easily allow for adding or upgrading the hard drive (20 to 70 gb)
17" (16.0"v.i.s.) dot pitch 0.26mm monitor
As with a television, screen size and picture quality enhances viewing pleasure and reduces eyestrain. Values for diagonal distance from corner to corner of the glass is the Viewable Image Size" (V.I.S). V.I.S is generally smaller than stated size of the monitor as in our example advertisement. "Notebooks tend toward smaller screens but 15" and 17" are common. Screens up 21" are now available with 17" the most popular for desktops. "Flat-panel" (FP) monitors, standard on notebooks, are now available for desktops. FP monitors have a much thinner front to back profile and thus require less space. Additionally, FP monitors make use of eye-saving "Liquid Crystal Display" (LCD). FP monitors are much more expensive than older technology "cathode ray tube" (CRT) monitors but typically last longer. If you opt for the CRT monitor you may want to consider a model with an eye saving flat glass screen. Picture quality is a function of several factors but typically higher resolution screens have smaller "dot pitch" values. Dot pitch ranges from 0.18mm to 0.39mm (the smaller the better) with 0.28mm being the largest value for a CRT monitor without undue eyestrain.
128Mb DDR graphics card
The video graphics card is a separate circuit board plugged into you computers main circuit board expansion slots. The video card has its own processing chip (coprocessor) and RAM memory that handles video information to relieve the CPU of that duty. Most late model computers come with a video card or easily accept installation and upgrades.
16x Max. DVD-ROM drive
Various types of disc drives are available. They offer the ability to upload and download data, record and play music and play movies. Drive ability is measured in multiples of a base standard of 150 kilobytes per second. (KBS) data transfer rate. . A 16X disc drive operates at a 16 X 150 KBS (2400kbs) transfer rate. CD ROM drives will read text and play music but not record. A CD RW drive will play music and allow you to record music or text onto record-able discs. DVD ROM and DVD RW share a similar relationship. A disc drive is a good means of "backing up" you computer hard drive information in case of failure.
4 PCI Slots, 1 AGP Slot
The computers main circuit board (motherboard) has sockets (expansion slots) for adding additional circuit boards. Currently, several Peripheral Component Interconnect (PCI) slots and one video dedicated Advanced Graphics Port (AGP) slot are common offerings. PCI slots allow quick installation of new circuit devices without extensive software reconfiguring (Plug and Play). AGP allows installation and efficient use of the video card.
4 USB ports
Serial ports and Parallel ports are standard equipment but an important item not to overlook is the Universal Service Bus (USB) port. USB offers high speed data exchange and allows several devices to be plugged into a single hub in a process know as "Daisy Chaining" greatly expanding the number of devices you can attach to one USB port. USB also allows devices to be disconnected and reconnected without shutting down the computer's main power.
Front audio jack
Audio jacks allow quick access for audio appliances. Often they indicate the presence of an Audio Card (AKA: sound cards) Audio cards allow the computer to process sound incoming and outgoing from equipment like microphones and external speakers and graphical and game devices like joysticks. The sound card enables the computer to function much like a stereo system.
Modems
Modems allow you to connect your computer to the Internet. Modems can be part of the internal or external circuitry of your computer. "Dial up" modems utilizing standard telephone lines are the most prevalent with a "56K " (56,000 bits per second) the minimum desirable. Most "off the shelf" computers come with 56k modem standard. Digital Subscriber Line (DSL) modems utilize high-speed digital connections via standard phone lines. DSL access is much faster than a standard 56k connection but more expensive. Additionally, DSL can remain continuously connected to the Internet so the dial-up process is eliminated. Cable modems allow very high-speed Internet access over the same types of lines cable television utilizes. The cable modem can be bought or leased from cable companies. If you select cable access you computer will need an Ethernet card installed. For possible DSL or cable Internet access check with you local phone company or Cable Company for availability and terms before you invest in the hardware.
Other stuff
Of course there is an expanding number of devices to make you computer more useful: printers, cameras, speakers, scanners, joysticks, networking options and dedicated backup devices.
NOTE: Questions or comments about the contents of this article should be addressed to the author, Vince Ory at VINCE_ORY@generalhealth.org
