If you're shopping for a PC, buy all the speed you can reasonably afford


August 24, 1992|By Michael J. Himowitz | Michael J. Himowitz,Staff Writer

Not long ago, I set up a mailing list of about 2,500 local organizations for my office. I did most of the work on my computer at home, an IBM-compatible 80486 machine with plenty of horsepower under the hood.

When I got to the office, I installed the data base on an 8-year-old IBM XT, which is about as high-tech as we get in the hinterlands.

I suddenly rediscovered life in the slow lane. At home, sorting the database by name took 30 seconds. On the old XT warhorse, it took seven minutes. Searching for organizations in a single ZIP code took three seconds at home; at the office it took 90 seconds.

It had been quite a while since I actually had to wait for a PC to do something. It drove me crazy. And today's complex programs -- most of which are far more demanding than the database I used for the mailing list -- will eat up all the system resources you throw at them.

If you're shopping for a PC, or you're paying someone to work at a PC, it's a good idea to buy all the speed you can reasonably afford.

Unfortunately, the hype and technobabble that erupts from most computer advertisers makes it difficult for buyers to figure out what they're getting. But some judicious shopping can satisfy your software's speed lust without breaking the bank.

First things first. Computers have to be much faster than they were a few years ago because users and programmers are demanding more.

Graphical environments such as Microsoft Windows and IBM's OS/2 operating system require the computer to do a lot more work than older character-based programs. The overall speed of a system depends on the type of microprocessor, the computer's internal clock rate, the amount of memory available, and the speed of your computer's disk drive.

IBM-compatible machines use chips designed by or patterned after Intel's 80X86 microprocessor line. The first IBM PC's, like the old-timer in my office, used Intel 8088 chips. Subsequently, IBM and its competitors used increasingly more powerful 80286, 80386 and 80486 chips. Except for low-end laptops, most IBM-compatibles sold today use 80386 or 80486 processors. They're referred to as 386 or 486 machines.

To make things more confusing, Intel sells two types of 386 and 486 processors. They're labeled DX and SX. Generally, DX computers will run a bit faster than cheaper SX machines using today's software, and they'll prove better investments as more programs are written that take advantage of their wider data path. Apple Macintosh computers use Motorola's 68XXX series of microprocessors. Early Macintoshes used the 68000. Later versions used the faster and more capable 68020, 68030 and 68040.

As the model number on the chip goes up, so does its speed and capability. Don't settle for anything less than a 386 in an IBM-compatible, or a 68030 in a Macintosh if you're planning on doing anything more than simple word processing.

You'll also have to consider the issue of different clock speeds within each chip line. Your computer's internal clock, actually a tiny crystal, sets up the delicate timing it needs to carry out software instructions. The faster the clock, the more instructions it can carry out in a given period of time.

Clock speed is usually measured in millions of cycles per second, or megahertz (Mhz). With IBM-compatibles, you can virtually take your pick of machines operating at 16, 20, 25, 33, 40, 50 or 66 Mhz.

Because only Apple makes Macintoshes, you're pretty much stuck with the clock rate Apple builds into your particular model. But in either case, you'll pay more money for more speed. If you're buying an IBM compatible, the minimum configuration you'll need to run Microsoft Windows or OS/2 comfortably is a 386 computer running at 25 Mhz (Don't buy advertising hype about slower machines). If you really want to be happy with your computer, don't settle for anything less than a 386DX running at 33 Mhz.

Another factor in a computer's speed is its hard disk drive. This effects not only high-speed graphical environments, but also database programs and even word processors with spell checkers.

Modern software is always reading from and writing to your hard disk. The faster the disk and controller, the faster your computer will operate. While there are various ways of measuring disk performance, the most common is the drive's ability to access a particular piece of data on the disk.

This is usually measured in milliseconds, and lower numbers are better. The absolute minimum you'll need today is a 28 ms drive, and I recommend a 15 or 19 ms drive. Luckily, even lowball computers are being packaged with fast disks.

Another major issue is memory -- the internal storage your computer uses for programs and data. If you don't have enough memory, Windows, OS/2 and the latest Macintosh operating system will often use disk space as a substitute, which is horrendously slow. Some programs won't run at all.

Here's where most bargain computers fall short, because they often come with only one or two megabytes of memory as standard equipment. If you're using a graphical environment on a PC, or if you're buying any Macintosh, you'll need four megabytes of memory to get decent performance out of your computer -- and eight megabytes is better.

Memory is cheap today -- $35 to $50 per megabyte (unless you buy direct from IBM or Apple). Load up with all you can.

How much does does speed cost? You might be surprised. The difference between an IBM-compatible 386/SX running at 25 Mhz and a 486DX running at 33 Mhz can be as little as $600, depending on the seller. For the additional money, you'll get a computer that runs two to three times as fast. It certainly won't keep you waiting.

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