How to choose a new PC. (personal computer) (COMPUTE's Getting Started With: Buying a New PC)
by Richard O. Mann

>From day one, savvy computer consultants have advised that the only way to buy computer hardware is to decide on the software you'll be using, then buy the hardware that runs it. In today's PC environment, that means deciding if you'll be buying [he latest, hottest applications as they appear, or if you'll be sticking with your tried-and-true favorite programs indefinitely. It means deciding if you'll be using Windows applications, multimedia programs on CD-ROMs, or computation-intensive programs such as CAD software. It's definitely possible to be perfectly satisfied with a low-end computer--as long as you don't try to do high-end things with it.

So decide what you're likely to be doing with your new PC before proceeding even one step further on the road to purchasing a new PC.

The Right Processor

Of course, the first decision is the processor, or CPU. The CPU determines how fast your machine operates, how well it handles advanced software such as Windows 3.1, and whether it can even run the most advanced new software. Each new generation of software seems to be written to strain the capabilities of the most advanced hardware available. (There are few, if any, programs that require a 486, but there are many that are painfully slow on anything less than a mid-range 486--say a 33-MHz model. And any new Windows application of any size and scope will need a zippy 486 to keep you from comparing its speed to glaciers and continental drift.)

With speed considerations and the low prices of today's 486 computers, anything less should be reserved for special situations where you know you won't be running any advanced software at all.

If you decide on a 486, you haven't narrowed the field by much. A bewildering array of different speeds, manufacturers, and feature sets result in more than two dozen choices in 486 chips, probably more by the time you read this. (At press time, the 486DX3 chips had not been officially announced, but we expect them any day.) Let's discuss the general classes of 486 chips.

486SX Versus 486DX. As with the 486SX and 386DX chips, the 486SX is a slightly limited version of the full 486DX chip. In the 486 line, an SX chip has the math coprocessor masked off, making it non-functional. The math coprocessor is an internal unit that handles floating-point mathematical operations much faster than the normal CPU. This doesn't matter except in computationally intensive programs, such as CAD applications and massive spreadsheet models. Check the price differential before deciding.

Clock Speeds. CPUs run at a rated speed. Undoubled speeds currently available are 16 MHz (megahertz, or million cycles per second) and 20 MHz, which currently are available only in SX versions, as well as 25, 33, 40, and 50 MHz. A chip labeled DX2 is clock-doubled, meaning its internal operations run at twice the normal speed, while communications with the rest of the computer run at the undoubled normal-speed. The 25 and 33 MHz speeds can be doubled to 50 and 66 MHz. The 486DX2/66 is, at press time, the fastest 486 chip available, but watch for the 486DX3/100 soon.

How important is clock speed? After all, something happening in a fiftieth of a second isn't noticeably faster than the same operation at a tenth of second. The speed differential shows up in Windows applications, in handling large databases, in loading programs, and other areas where you typically have to wait for your computer to catch up with you. Going from a 386DX/16 to a 486DX2/66 is dramatic. Programs load instantly, Windows applications move along at a tolerable speed, and multimedia applications work in real time.

As new software comes out, however, expect that it will stretch your computer to its limits of speed, so get the fastest untiil you can afford--unless you're a particularly patient sort of person who doesn't mind a few seconds waiting now and again.

Other 486 Chips. You'll also see 486SL and SLC chips, which have additional power management features for use in laptops, and a raft of oddly named chips from AMD (American Micro Devices) and Cyrix. These two manufacturers, along with others, make chips they claim to be functionally equivalent to the Intel chips we're more familiar with. They're less expensive and experience has shown them to be fully reliable, fully compatible chips. There are technical differences, however, that you might want to be aware of before making a purchasing decision, such as internal cache sizes, number of transistors, and so on.

Pentium. Intel's newest and still very pricey chip is the Pentium. Conventional wisdom at this point in the product/price cycle is that most of us don't need that much power yet. Until the cost comes down and more software is rewritten to take advantage of the Pentium's advanced features, most of us won't be able to justify the cost.

The Right Bus

The computer's data bus is the channel outside the CPU that carries data and other electronic instructions between all the boards and devices in the computer, including zipping data around the motherboard to the RAM memory chips. As fast as the CPU is processing data, if its instructions are sent out at a lower speed, the whole process must slow down.

The standard bus used in most PCs today is still the old IISA (Industry Standard Architecture) bus from the IBM AT computer. The EISA (Extended ISA) bus runs at the same speed but transfers twice as much data in each pulse. Though the EISA bus was a good idea, its higher cost has limited it. It's primarily used in network file servers and business machines where heavy data transfer makes it worth its cost.

Another term you'll hear is Local Bus. At first, local bus designs were proprietary, but a standard local bus design has emerged, called the VESA Local Bus or VL-bus. Intel recently has introduced the PCI bus, its version of local bus design. The main effect of the local bus so far has been to dramatically speed up video performance, but other devices can be attached to the VL-bus with measurable performance gains. Most local bus systems now available offer a few local bus slots for high-speed devices and ISA slots for everything else. Local bus costs more than a straight ISA bus, but the increased video speed alone makes it a necessity for Windows users.

The Right Amount of Memory

Many computers still come with 2MB of RAM. Don't be suckered into that trap. Windows applications say they'll run with 2MB, but the best you could say is that they walk--or perhaps crawl--with 2MB. You need 4MB minimum, but buy 8MB if you can afford it. Going to 8MB can make Windows run as much as twice as fast. Beyond 8MB, speed increases are minimal with most of today's software. On the other hand, if you're planning on using OS/2 or Windows NT, then 16MB is the minimum.

Also check with the vendor to see exactly how you upgrade memory. If you buy 4MB now and decide later to expand to 8MB, it may cost you more than buying the 8MB up front. (Some memory schemes require you to pull your 4MB of RAM chips, discard them, and replace them with new higher-capacity chips to achieve 8MB).

The Right Hard Drive

Get the biggest drive you can afford unless you're one of the few who never buy new software and don't plan to do much with Windows. Choices here include the current standard IDE drive systems and SCSI drives. SCSI can be faster, but it isn't really necessary until you get into the really large drives that few of us will be buying--drives in the 1 gigabyte range. For the best price/performance ratio in standard size drives, stick with IDE.

How much hard disk space is enough? Those of us who've been using PCs since the beginning to know how rapidly the threshold of enough storage space rises. One thing you can count on: The drive your PC vendor packages with the standard system is unlikely to be adequate for any length of time. In an era when Strike Commander, a game you can buy at the mall for under $50, takes 28MB of hard disk and any self-respecting Windows application takes 15MB more, your drive will fill up before your next birthday. Buy as much drive as you can afford, but don't take less than 200MB if you can help it.

One option you might consider: I found t'at I could buy two 340MB drives for less than one 600MB drive. Two drives also can give you more options and backup flexibiility than a single larger drive.

The Right Video Adapter

Video has settled into a reasonably comfortable technological valley. There's no present challenge to the Super-VGA standard; all the action is in adding memory to SVGA adapter cards along with a local bus to achieve much faster throughput, higher resolution, and more colors. Windows has a tendency to make you wait while it redraws its graphics screens. Speeding things up through more on-board video memory, an accelerator chip, and local bus has dramatically pleasing results.

The capabilities of video cards are now given in resolutiion and number of colors provided (really a function of the on-board memory). Windows works with multiple resolutions; 1,024 by 768 (pixels) is the practical high limit for normal monitors. (Higher resolution results in smaller images; 1,280 by 1,024 requires a 20-inch monitor to be practical.) Many Windows users with 14- or 15-inch monitors find 800 by 600 to be a comfortable compromise between getting more on the screen and the smaller image sizes. At any rate, you'll want a practical minimum of 256 colors at 800 by 600, which requires only 512K of video memory. Another 512K of video memory (for a total of 1MB) buys you 65,000 colors at 800 by 600 or 256 colors at 1,024 by 768, which should be enough for anyone without a mega-screen monitor. You absolutely need 256 colors at 640 by 480 (the standard DOS-sized screen and resolution) to run any modern multimedia or game software, so don't get less.

A standard VGA card is called a frame-buffer card. It relies on the CPU to process all the video information while it merely stores the data for an individual screen image, then spits it out on the screen while accepting another frame from the CPU.

For newer technology, take a look at an accelerator card--usually called a Windows accelerator and because DOS applications get no benefit from it. Windows accelerator cards contain a chip that takes a large portion of the video processing from the CPU, leaving the CPU free for other tasks. Accelerator chips are hard-coded at the factory and require software drivers to interface the CPU to the card's functions.

For today's normal user, Windows performance is a major issue, so go with a local bus Windows accelerator card with enough memory to provide the resolutions that you'll want.

Consider the manufacturer of your video card. A well-known name is best because you're going to need future upgrades of the software video drives as new versions of Windows come out. You must know who made your video card and how to contact the company for upgraded drivers. New Windows drivers to deal with quirks in new software are a fact of life, even without new Windows versions. Be sure to get a standard card.

The Right Monitor

Monitors present another array of not widely understood technical terms to confuse the unwary buyer. The first spec is easy to understand--size, measured in diagonal inches of screen. For years, the 14-inch screen has been standard, but 15-inchers are increasingly popular. An extra inch doesn't sound like much, but as resolutions increase and Windows icons get smaller and harder to see, that extra inch can be surprisingly helpful.

If you'll be doing heavy graphics work, desktop publishing, or other work requirement a large display area, consider a 17-inch or 20-inch screen. However, don't spend the money required for these larger screens without a hands-on test to see if the difference is really worth the extra cost.

Vertical Scan or Refresh

Rate. The monitor paints an image on the screen by shooting an electron beam at individual pixels on the screen. The beam scans in a tight line horizontally across the screen, returns to the beginning of the next line, and does it again. The second number in the resolutions we've talked about is the number of lines per screen. At an 800 by 600 rate, the beam is lighting 800 pixels for 600 rows.

The vertical refresh rate is the number of times per second the beam paints the entire screen. Refresh the screen too few times and you'll notice an annoying flicker on your screen. The Video Electronic Standards Association (VESA) recommends 70 to 72 Hz (cycles per second), but its guidelines allows for as low as 56 Hz at 640 by 480 and 60 Hz at higher resolutions. The higher the vertical refresh rate, the better the image you'll see.

Interlaced Versus Non-interlaced. Monitors can accomplish vertical refreshing in one of two ways: interlaced or noninterlaced. Interlaced scanning, the older, less expensive way, paints every other line top to buttom, then returns to the too to fill in the remaining lines. Noninterlaced scanning simply works down the screen line by line in a single pass. Interlaced scanning produces much more flicker.

Obviously, then, noninterlaced scanning is preferable. Watch out for less expensive monitors that switch to interlaced scanning at higher resolutions. Don't be fooled by interlaced monitors that claim a 90 Hz refresh rate; that's the rate to refresh only that the screen (every other line), and translates to an actual rate of only 45 times per second.

DotPitch. A widely quoated monitor specificaions, dot pitch refers to the spacing between the phosphors on the back of the screen--the phosphors that the electron beam hits to light up individual pixels of the screen image. If the phosphors are too widely spaced, the monitor will be unable to create enough pixels at high resolutions.

You'll find dot pitch measured in hundredths of a millimeter. a 14-inch monitor needs a dot pitch of .35 mm to effectively display a 640 by 480 screen. At 800 by 600, it drops to .28 mm, and 22 mm is required at 1,024 by 768. On larger monitors, a dot pitch of .24 will display 1,024 by 768 and all other lower resolutions.

Other features. Flat screens or vertically flat screens (curved horizontally but not vertically) are less susceptible to glare than curved screens, but are much harder to manufacture.

a set of manual controls should be available on the front of the monitor. Brightness and contrast will be there, of course, but horizontal and vertical size and position are important as well. Different programs seem to put their images in slightly different sizes and positions on the screen; the ability to alter the size and position of the image is helpful.

A built-in tilt and swivel stand is necessary. A few monitors designed for use in multimedia systems come with stereo speakers built in, eliminating the desk space needed for speakers and reducing the cable clutter surrounding your system.

The Right Case

It'll probably surprise you how important getting the right case or box for your computer can be. Desktop PCs come in four basic case sizes: standard desktop, slimline, tower, and mini-tower. The desire to save desktop real estate may incline you toward the slimline case, but you should know that the smaller cases have very little room for expansion and can be a nightmare to upgrade.

If you'll be adding a sound card, a CD-ROm drive tape backup, and internal modem, a network interface card, a removable-cartridge storage system (such as a Bernoulli Box or SyQuest cartridge system), a scanner, or any of a host of other peripherals, you'll be out of internal space to install them in no time. A typical slimline case has two or three drive bays and three internal expansion slots.

Smaller cases also may require non-standard sized motherboards. Replacing them either for upgrade or repair purposes can be unduly difficult, and smaller cases can make it difficult to access components for repair.

To save slots, some smaller-case computers put video or other functions on the motherboard, effectively blocking you out of changing or upgrading those functions.

Leave expansion room unless you know for certain you'll never need to add more than a few cards or drives and you won't want to upgrade the motherboard.

Other Components

Insist on a 3.5-inch high-density floppy disk drive and get a 5.25-inch high density floppy drive as well, if possible. It's possible to get along with just a 3.5-inch drve now, but you'll encounter times when it's convenient to have both sizes. You can buy any software or exchange data with any PC anywhere if you have both sizes of drive.

If your plans include online work with the national networks, local bulletin board systems, or dialing up to your office system, you'll need a modem. A 2400-bps modem is the bare minimum needed, but for a little more money you can bag a 14,400-bps fax modem that'll give you high speed connections anywhere on the planet. Go for the internal modem if possible to leave your serial ports available for other uses and reduce desktop clutter. Also, some PC manufacturers have had trouble getting the high-speed 16550 UART-equipped serial ports necessary for high-speed modem communications to work with their clock-doubled 486s. An internal modem bypasses that problem entirely.

Tape backup is rapidly becoming common, even in home computers. PCs with 200MB-plus hard drives take forever and require dozens of floppy disks to back up. A $250 tape unit takes all the fuss and bother out of this necessary task, backing up 250MB at a whack, unattended. Internal units occupy one drive bay. Avoid non-standard interfaces (SCSI or IDE are standard).

If you're buying from a local store, you may be able to specify a particular keyboard. Keyboards are totally a matter of personal preference, so if it's posible, try out the keyboard to ensure that you get one that feels right to you. If no acceptable keyboards are offered, you might consider buying it separately from one of the front-line keyboard makers such as Northgate or Keytronic.

You'll also want a mouse and joystick (if you're a gamer) thrown in. Mice are fairly generic creatures, but buying the new Microsoft mouse 2.0 will get you Microsoft's new mouse driver version 9.0 with a bunch of wonderful new features designed to make Windows easier to use

And lastly, as an incipinet Carpal Tunnel Syndrome sufferer, let me advise you to take precautions to protect your wrists. Even the inexpensive foam rubber wrist rest that sits in front of your keyboard can mame a remarkable differnce in the stress on your wrists.

The trick to buying a PC is finding the right blance between price and features. You may need to trade the least important features for a price you can live with. Or you may need to hold off for a few months and let the prices come down. But don't wait forever; if you wait for the lowest prices ever, you'll never buy, and there will always be price cuts and never, PCs just around the corner.