Computer buying guide

Before you decide to replace a sluggish computer, try these steps to beef up its performance:

Delete programs you no longer use. If that isn't enough, and if the computer is no more than four years old, add 1GB of memory. Adding memory is an inexpensive and easy way to upgrade your computer.

If you're running out of hard drive space, burn your music, photos, and videos onto CDs or DVDs, or onto an external drive, and delete them from your hard drive. To gain storage space, consider adding a hard drive. (Adding an external drive is an upgrade even a novice can do.)

If none of that works, and the computer is more than four years old, it's probably time to replace it. Be sure to recycle your old computer, but don't forget to wipe your hard drive first. We recommend Eraser, available free at http://www.heidi.ie/eraser, for Windows-based computers. Apple computers have an erase feature built in.

Windows 7 is the latest iteration of Microsoft's operating system. It costs from $120 to $200 off the shelf. Eligible college students can grab an upgrade for $30 at www.theultimatesteal.com.

An Apple computer running Mac OS X is a fine alternative to Windows. Apple computers can also run Windows, but you have to purchase and install it yourself. The latest version is Lion; current Apple users can upgrade for $30.

The desktop computer has become just another appliance you use every day. However, consider these pros and cons of desktop computers in general:

Laptops let you use your computer away from your desk, but you pay for that mobility with a smaller screen and keyboard, a higher price, and sometimes, reduced performance. Technological advances have lessened the performance compromises somewhat, however. Whether your main consideration is portability or power, screen size will be an essential factor in deciding which type of laptop is right for you:

Inexpensive and portable, netbooks are basically downsized laptops with 10-inch screens. They weigh about 2 to 3 pounds and cost from $300 to $400. Netbooks are suitable as secondary computers for performing routine tasks. The best offer lighter weight, larger keyboards and trackpads, and longer battery life. All include a memory card readerand webcam.

If you plan to watch videos on your netbook, we recommend a model with Intel's beefed-up dual-core Atom processor. (If you want to watch a DVD, you'll need to buy an external optical drive.)

Lightweight and highly portable, tablets are made to be carried wherever you go. They're multifunctional, serving as Web browser, e-book reader, digital picture viewer, movie viewer, and music player. All our top picks are very easy to use, have a display with a wide viewing angle, and can download apps from a market approved by the maker of its operating system. They weigh from just under a pound to about 1.5 pounds and have 7- to 10-inch touch screens. All have webcams. In our tests, battery life ranged from 4 hours to nearly 12 hours. (See our Tablets buying guide for more.)

Also known as the CPU (central processing unit), the processor is the computer's "brain," responsible for processing information. Performance is the most important factor when choosing a processor, and that is determined primarily by the number of cores it has and its clock speed.

Intel and AMD are the dominant processor manufacturers. Within each company's product lines are various processor families. Intel's include the low-end Atom, Celeron, and Pentium; the midrange Core 2 and Core i3; and the high-end Core i5 and Core i7. AMD's processors range from the low-end Turion II, to the mid-range Athlon II, to the high-end Phenom II. Intel's new CPUs are the second generation Core i3, i5, and i7. They add an automatic speed boost when needed and improved graphics and video capabilities. AMD's new processors are called Fusion. The A Series of Fusion integrates discrete graphics into the processor. As a result, you can play more challenging videogames on these computers without needing separate graphics.

Processors with multiple cores can process more data simultaneously. You can often tell how many cores a processor has by its name. A Core 2 Duo has two cores and a Core 2 Quad has four. A Phenom X3 has three cores. It's not always that clear, however; some Core i5 processors have two cores and others have four. The Core i7-980x has six.

Clock speed, measured in gigahertz (GHz), determines how quickly a processor can process information. Within a processor family, the higher the clock speed, the faster the computer. Clock speeds typically start at around 1GHz for a mobile processor and can exceed 3GHz for a desktop processor.

Power consumption is another important factor when choosing a processor, especially for laptops--lower power consumption translates to longer battery life.

When buying a computer, make sure it has a processor that will be fast enough to handle your needs. Whether you are buying a desktop or a laptop, avoid computers that use the AMD Athlon Neo, Turion Neo, or Sempron processor, the Intel Atom or Celeron processor, or the Via Nano processor. For basic tasks such as browsing the Web and checking e-mail, opt for a low-end dual- core processor such as the Intel Pentium Dual- Core or AMD Athlon/Turion X2. If you plan to use your desktop or laptop for entertainment, such as watching videos or playing games, get a faster processor such as the Intel Core 2 Duo/Quad, Intel Core i5, or AMD Phenom/Phenom II. If you're a hardcore gamer or plan to edit high-definition (HD) video, buy a computer with a high-end processor such as the Intel Core i7. For less-intensive uses such as productivity tasks, the Core i3 should suffice. When buying a netbook, stick to the slow but efficient Intel Atom processor.

The computer's memory, or RAM, is used to store data temporarily while the computer is on. The more memory a computer has the faster it is, up to a point. Memory is measured in gigabytes. On desktops, 8GB is common and a few laptops include up to 6GB. We've found that for anything other than heavy multitasking or video editing, 4GB is plenty. Most store-bought systems with the Intel Core i3, i5, and i7 processors have 8GB. If you configure a PC at a manufacturer's site, choosing 4GB can save you up to $140. Netbooks typically come with 1GB of memory, which is adequate.

A growing number of laptops include fingerprint scanners as a convenient alternative to typing a password when logging in. Some laptop manufacturers, including Lenovo and Toshiba, are now incorporating face-recognition technology. Lenovo's IdeaPad uses VeriFace technology when you log on. With VeriFace, your face is scanned, via the laptop's webcam, and then scanned again to make sure it matches the initial scan every time you log on. We found facial recognition easier to use but less secure than a fingerprint scanner. But it didn't work as well in low light and for some faces with glasses. In addition, we found at least one report of the software being fooled by photographs of people's faces.

Many people choose PCs running Windows because they're less expensive than Macs. Others choose PCs because they have a wider selection of games or they want to be fully compatible with Windows programs. If you go with a PC, you have a choice of several versions of Windows 7, each with its own hardware requirements. Windows 7 is less prone to crashing than the previous version, and has more refinements and features but fewer annoyances. We recommend Home Premium as the Windows 7 version for most home users.

Macs are more expensive but are stylish, and they're also immune to most viruses and spyware. Apple's support has been tops in the industry in our surveys. While the company's phone support is free for only 90 days, you can get unlimited technical support through the Genius Bar if you live near an Apple Store. Apple's current operating system is OS X Lion.

Also known as the video card, GPU, or graphics card, this is responsible for drawing what you see on your screen. There are two types of video adapters: integrated and discrete. The vast majority of computers sold have integrated video, which is slower and uses up part of your system's memory. That said, integrated video is fine if you don't play complex 3D games such as The Sims or World of Warcraft. Otherwise, choose discrete video, which is faster and uses its own video memory. If you choose discrete, look for at least 256MB of video memory. Gamers should get 512MB or more of video memory.

Until recently, retailers rarely offered a graphics processor with dedicated video memory on a laptop smaller than 17 inches. Now, many 15-inch models have one. These laptops generally have powerful main processors and generous hard drives, making even 15-inch models appealing to gamers. Prices on these models have come down, as well.

If you're buying a desktop, check to see which video outputs it has. Almost all desktops have a VGA (analog) output, but some also have a digital output, either DVI (digital visual interface) or HDMI (high-definition multimedia interface). VGA is fine for most uses, but for a cleaner, crisper image on large displays, go with DVI or HDMI. You may have to buy a cable, which costs around $10. If you're buying a laptop, you can use a VGA output with a projector for delivering presentations. Newer desktops and laptops might have an HDMI output to feed video to an external HDTV.

Also known as a hard disk, this is where your programs, documents, music, photos, and videos are stored. Bigger is better. Hard drive sizes are measured in gigabytes and commonly range from 250GB to 1TB (terabyte). Though size matters, speed is equally important. Speed is measured in rpm (revolutions per minute). A slow hard drive will take longer to start up the operating system and programs, and to complete tasks (such as installing programs or scanning your hard drive for viruses). Get a desktop with at least a 7,200rpm hard drive and a laptop with a 5,400rpm hard drive.

Hard drives often fail after a while, so you need to back up your data periodically to avoid losing it. The best option is an external hard drive. These connect to your computer through its USB, FireWire, or eSATA port.

Some high-end desktops and laptops can be configured with a RAID (redundant array of independent disks) setup. These computers have two or more hard drives. There are several types of RAID, the most common being RAID 0 and RAID 1. RAID 0 distributes your data across multiple hard disks, which can greatly improve speed. But if one fails, you'll lose data on all your drives. RAID 1 automatically copies data from one drive to the other. If one crashes, all your data will be safe on the other.

A concept that could ease the agony of a crash is cloud computing. With Apple's iCloud service, for example, all your data also resides on the company's servers. Any documents you put on iCloud will be available to all your iCloud devices.

SSDs (solid-state drives) are on the cutting edge of storage technology, allowing your computer to access data without the moving parts required by a traditional hard drive. So-called flash drives don't have the spinning disk of a conventional hard drive, so they use less power, work quieter, and should be more resistant to damage from rugged use. And because there are no moving parts, they promise quicker access to data. But they still cost several times that of traditional hard drives and have smaller capacities.

This lets you read and write to CDs, DVDs, and Blu-ray discs. DVD burners (also known as DVD+/-RW) are standard gear on today's computers. They can read and write to CDs and DVDs so you can back up your home-video footage or digital photos, for example. Recordable CDs (CD-R) can hold up to 700MB of data. Recordable DVDs (DVD+R, DVD-R, or DVDRAM) can hold up to 4.7GB (single layer) or 8.5GB (dual layer) of data.

Blu-ray Disc (BD) drives are the newest standard. They're capable of playing Blu-ray movies and can store 25GB (single layer) or 50GB (dual layer) of data, respectively almost six times the capacity of a singleor dual-layer DVD.

For desktops: Screen sizes (measured diagonally) generally range from 15 to 24 inches, but you can find even larger ones. The most common screen sizes are 19 and 20 inches.

Most are wide-screen, which fit widescreen movies better but give you less screen area per inch. Those who plan to edit photos or videos may want to pay attention to differences in color, viewing angle, contrast, and brightness. Monitors are often less expensive when bundled with a new computer.

For laptops, a 15- to 16-inch display should suit most people. Displays that are 13, 14, and 17 inches are also common. The screens on most laptops are glossy instead of matte. Glossy screens have moresaturated colors and deeper blacks but are also much more prone to glare. Like desktop displays, most laptops have wide-screen displays to fit wide-screen movies better.

LED-backlit displays provide more efficient use of power, resulting in longer battery life. In most cases, color on LED-backlit screens is not significantly different than that on other types of displays.

Borrowing from the tablet realm, companies have begun experimenting with touch screens on some netbooks, such as the Lenovo IdeaPad Netbook Tablet 06517HU, which has custom, touch-enabled multimedia apps, and desktops, such as the HP TouchSmart 610z and 610xt. Several all-in- one systems in our Ratings also include multi-touch capability, which lets you use two or more fingers to zoom and scroll.

For laptops: When not plugged in to a wall outlet, laptops use a rechargeable lithium-ion battery for power. Laptops go into sleep mode when used intermittently, extending the time between charges. You can lengthen battery life if you dim the display, turn off wireless when it's not needed, and use only basic applications. Playing a DVD movie uses more battery power than other functions, but most laptops should be able to play one through to the end. Many laptops can accept an extended battery, adding size and weight but giving as much as twice the battery life. Some laptops, most notably Apples, have nonremovable batteries, which may be costly to replace when run-time starts decreasing.

For desktops: Form factors for computers are more varied now. In addition to the most common format (tower), you can find all-in-one and small-form-factor (SFF) computers. Mainstream computers usually come in towers, which fit on top of or under a desk. All-in-one computers, such as the Apple iMac and HP TouchSmart, pack all the components into the same enclosure as the LCD display, with only the keyboard and mouse separate. Sony, HP, Dell, and Gateway also have all-in-one models. SFF cases include the Dell Studio Hybrid and the Apple Mac mini.

For connecting to the Internet, all desktops come with an Ethernet port that lets you run a cable between your desktop and your router. If it's not possible to run such a cable through your home, consider a Wi-Fi adapter. Some desktops have this built in. If not, you can buy one for about $25 and plug it into a USB port. You'll also need a wireless router. Laptops come with wireless built-in, and most have a port for connecting an Ethernet cable.

Wireless adapters mostly use the newer 802.11n standard (which is backwardcompatible with 802.11g). Unless you have an exceptionally large house, you don't need to buy an 802.11n wireless adapter. 802.11g is slightly less expensive and fast enough for most people's needs, and its range is wide enough to cover a medium-sized house. If you do select an 802.11n adapter, make sure your router supports 802.11n as well.

Intel's WiDi capability is built into new computers that have a second-generation Intel Core i-series processor (with a four-digit processor number). WiDi lets you wirelessly stream video from your laptop to a TV. As mentioned earlier, it requires an external box, which costs $120 from Netgear or Belkin.

WiDi supports only 720p resolution. Similar technologies, such as WiGig, Wi-Fi Direct, WHDI, and Wireless HD, support 1080p HD. Apple TV lets you wirelessly stream Internetbased video to a TV without a computer.

Most of the mice that come bundled with desktops are optical, meaning light sensors on their undersides track movement. Apple offers its Magic Mouse, which has a touch-sensitive top surface that works in a similar manner to a multi-touch touchpad. Some mice are ergonomically contoured to match the shape of your palm, while others are designed to be stylish. They can also be either wired or wireless. If you have a wireless mouse, you won't have to deal with a cord, but you will have to recharge or replace the batteries every few months.

Most laptops use a touchpad in place of a mouse; you slide your finger across it to move the cursor. You can also program the pad to respond to a "tap" as a "click," or scroll as you sweep your index finger along the pad's right edge. Touchpads come in various sizes; the larger ones let you move the cursor farther across the screen without lifting your finger. Some let you use multifingered gestures for zooming and rotating images. An alternative system uses a point- ing stick the size of a pencil eraser in the middle of the keyboard. If you prefer, you can attach a USB or wireless mouse or trackball.

Most computers come with a standard wired keyboard. Some keyboards have CD (or DVD) controls that let you pause, play back, change tracks, and change the volume. Some also have additional keys to expedite getting online, starting a search, launching programs, or retrieving e-mail. Like mice, keyboards can also be wireless.

On most desktops, except for all-in-ones, speakers are optional. Computers with three-piece speakers include a subwoofer, which delivers deeper, more powerful bass. If you plan to turn your computer into a home theater, consider six-piece speakers, adding two rear and a front speaker for surround sound. You'll also find connections for audio input and headphones.

The small speakers built in to laptops often sound tinny. And a familiar brand name like Altec Lansing or Harman-Kardon doesn't mean they'll sound good. Headphones or external speakers deliver much better sound. Some larger laptops include better speakers and even a subwoofer for deeper bass.

The ports to look for on a computer include USB (including the new USB 3.0), FireWire, Ethernet, eSATA, and S-video or HDMI. Apple desktops and laptops now have a port called Thunderbolt, which is by far the fastest data-transfer port. USB ports let you connect many add-on devices, such as digital cameras or external hard drives, as well as flash drives for copying files to and from the hard drive. Having these ports at the front of the case makes connecting devices more convenient. An Ethernet port or wireless network card lets you link sev- eral computers in the household to share files, a printer, or a broadband Internet connection. FireWire or IEEE 1394 ports are used to capture video from digital camcorders and connect to other peripheral devices.

An eSATA port lets you connect an external hard drive for faster file transfer than with USB. Some combo ports can serve as either eSATA or USB ports. An S-video or HDMI output jack lets you run a video cable from the computer to a TV so you can use the computer's DVD drive to view a movie on a TV instead of on the computer monitor.

Media-center PCs (equipped with TV tuners) can also capture video from a VCR, letting you copy tapes to DVDs. Other slots to look for on a new computer are memorycard readers for flash cards.

For laptops: Most laptops have at least two USB ports for easy hookup of, say, a printer, digital camera, or scanner. Also common are a wired network (Ethernet) port, a FireWire port for digital-video transfer, and an internal wireless-network (Wi- Fi) adapter. Some laptops also have an internal Bluetooth wireless adapter to link to a Bluetooth-capable cell phone, camera, or another laptop.

For laptops: An ExpressCard slot lets you add a cellular modem.

For laptops: Some offer a connection for a docking station, a $100 to $200 base with connections for a monitor, keyboard, mouse, printer, network, and power. By fitting your laptop into this base you can connect to all these devices at once.

For tablets: Some tablets also have optional docking stations that add a keyboard.

Gateway and eMachines are owned by Acer. The companies do not sell their products direct to consumers, unlike most other computer makers. Acer Aspire products run the gamut of consumers from budget to high end.  The Aspire One line is Acer's netbook offering. Among its other lines are all-in-one desktops, Revo entertainment computers, and Veriton desktops. Acer also produces Android-based tablet computers and offers a Chromebook that runs Google's Chrome operating system.

Apple computers usually cost more than Windows-based systems. Apple computers use Apple's operating system, Mac OS X. Macs can also run Windows. Mac OS X has had fewer problems with viruses and other malware. The company primarily offers several consumer lines, the MacBook Pro (laptops), the iMac (all-in-one desktops), the Mac mini (a small, budget desktop), and the iPad (touch-screen tablet). Apple recently discontinued its MacBook line of laptops.  The Mac Pro desktop is it's professional line. Apple's telephone tech support is limited to three months, but you can get unlimited free tech support at the Genius Bar in Apple stores.

Asus has an extensive line of EeePC netbooks.  Laptops range from budget to high end.  Its Essentio desktop brand is limited to value and midrange models.  It's line of all-in-one computers includes the EeeTop. Its EeeBox refers to entertainment desktops. Asus also produces Android-based tablet computers under the EeePad name. Asus does not sell its lines direct to consumers, unlike most other computer makers.

Compaq is owned by HP. Its value line of desktops and laptops is sold under the Compaq Presario brand.

Inspiron is Dell's mass-market line of laptops and desktops. For higher performance and gaming systems, Dell offers XPS laptops and Studio XPS desktops.  Dell's compact desktop offerings include the Inspiron Zino. The Inspiron Mini is its netbook series. For hard-core gamers, Dell offers Alienware systems.  Inspiron One is its all-in-one brand with optional touch screen. Dell Streak is it's line of Android-based tablet computers.

Gateway is owned by Acer. The companies do not sell their products direct to consumers, unlike most other computer makers. The NV and ID series are Gateway's budget and mainstream laptops.  DX and SX are the budget and midrange desktop lines.  FX is Gateway's high-end desktop, and ZX is its all-in-one.  LT series is its netbook line.

HP is the No. 1 seller of desktops and laptops in the United States. In laptops, it offers the midrange Pavilion line, the budget G-series line, and the high-end premium Envy line. In desktops, it offers the budget and midrange Pavilion line, a Pavilion Slimline (slimmer design), and the Pavilion HPE high-end desktop.  There are two all-in-one lines, the Omni, and TouchSmart (with touch screen).  For netbooks, it's the HP Mini line.  HP discontinued sales of its TouchPad tablet several weeks after it launched.  But it still provides updates to its webOS, the operating system used by the TouchPad. 

Lenovo has been expanding its offerings to consumers. IdeaPad is its midrange consumer laptop line and includes the S series of netbooks. The Essential series is Lenovo's budget line of laptops and desktops.  Lenovo ThinkPads are its business notebooks; ThinkCentre are business desktops.  IdeaCentre is Lenovo's brand of midrange consumer desktops and all-in-ones.  Lenovo also produces Android-based tablet computers under the IdeaPad name for consumers and ThinkPad name for business.

Samsung offers a variety of laptops ranging from slim & light to desktop replacements, to its N-series of netbooks.  Samsung also produces Android-based tablet computers under the Galaxy Tab name and a Chromebook, which runs Google's Chrome operating system. It does not sell its lines direct to consumers, unlike most other computer makers.

Sony's variety of laptops ranges from the thin & light Y and Z series, to the mainstream C and E series, to the high-end F & S series, which includes 3D. All-in-one desktops are the JS series and L series (which includes 3D), midrange and high end respectively. Its W series is netbooks, and its mini-laptop is called the P series.  Sony also produces Android-based tablet computers under the Sony Tablet name.

Toshiba sells laptops, desktops and netbooks. Its consumer laptops include the Satellite line (budget and midrange), and the Qosmio line for high-end gaming.  The Toshiba Mini is its netbook line.  Satellite Pro, Tecra, and Portege are its business laptop lines.  After a long absence, Toshiba recently re-entered the desktop market with its DX line of All-in-One PCs. Toshiba also produces Android-based tablet computers under the Thrive name.

eMachines is owned by Acer and sells budget desktops and laptops under the E, EL and ET series.  The company does not sell its products direct to consumers.

Shop at an online retailer. Our subscriber surveys have found them generally superior to walk-in stores for selection and price. You can also save money by using coupon and forum sites such as Techbargains, FatWallet.com, and Ebates, which tend to provide information on rebates.

If you have special needs, order from the manufacturer's website. Menus show you all the options and let you see how a change affects the overall price. Configure-to-order will often give you choices you won't get if you buy an offthe- shelf model. But be sure to double-check your choices before ordering, and look for unwanted items some manufacturers include by default.

January, July, and October are good times to shop; new models show up in stores at those times, meaning older inventory must be cleared out to make room. If a computer you like isn't on sale, ask for a better price. Apple usually offers free iPods and educational discounts to students buying computers during the back-to-school season. Macs aren't discounted that often, so take advantage of the price cuts that usually occur around the time Apple announces new models. That's when other retailers, such as Amazon.com, MacConnection, and MacMall, tend to clear out older stock. Models from other PC brands may also be discounted when their successors arrive.

Check out coupon and deal sites such as Techbargains.com, FatWallet.com, and Ebates.

Especially when you're buying a laptop, try it before you buy it, if you can. The keyboard shouldn't bend under continuous tapping, the touchpad should be large enough so that your finger can cover the span of the screen buttons should be easy to find and press. The touchpad should also have a dedicated scroll area. Carry the laptop around for a few minutes and make sure it isn't too heavy or too big. If it's been on for a while, feel the bottom. A laptop shouldn't get hot during use, and it should run quietly. Glossy screens are now standard on most laptops. Several manufacturers have added antireflective coatings, with mixed results. Finally, manufacturers are emphasizing design as much as substance; find a laptop that suits your style.

Some computers meet the new Energy Star standard for efficient power use. Energy-use guidelines cover three operating modes--standby, sleep, and running--with systems enter- ing sleep mode within 30 minutes of inactivity. Power supplies also need to operate more efficiently. You probably won't notice much difference in the operation of your computer, but your electricity bill might go down a bit. Look for the Energy Star label on qualified computers. Prices won't increase because of the new standard, according to a representative for the Energy Star program. Another standard is EPEAT, which offers guidelines on what materials can be used in a computer. Depending on how well each computer meets the criteria, it is rated bronze, silver, or gold. A list of EPEAT-compliant systems can be found at www.epeat.net.

MMost manufacturers also have recycling programs that help you to dispose of your old computer, but the programs vary considerably by company.

Buying a laptop for a college student