Positive's high-performance PC offers speed at value price

Computer file

January 21, 1991|By Lawrence J. Magid | Lawrence J. Magid,Los Angeles Times

I don't often review IBM compatible computers. There are so many on the market and, in many cases, it's almost impossible to tell them apart. But once in a while I come across a machine that distinguishes itself. Positive Corp.'s 486-25 qualifies because it delivers high performance at a modest price.

At $2,999, the 486-25 isn't inexpensive. It is an excellent value for people who need a high-performance PC. The machine is equipped with an Intel i486 central processing unit (CPU) that runs at 25 megahertz (Mhz). This is the first fully equipped 486 machine that I've seen for under $3,000.

The basic system comes with 2 megabytes of memory and a 106-megabyte hard disk. It has two floppy drives (1.2 megabyte and 1.44 megabyte), a mouse, a color VGA monitor (1024 by 768 pixel) and a keyboard. A 128-kilobyte memory cache improves performance by storing the most recently used instructions in a special bank of high-speed memory. There are two serial ports and a parallel port. It also comes with the MS-DOS 4.01 operating system, Windows 3.0 graphical user interface and working models of several Windows programs.

The company's distribution strategy is also unique. The machine is available at the Price Club and Sam's Warehouse Membership Department Stores. It is also available by mail order for about $200 more. Warehouse stores are not known for their customer service, but Positive offers its own toll-free support line as well as a one-year warranty and free on-site repairs for the first 30 days.

The machine's 486 CPU is faster and more powerful than earlier CPUs designed for IBM compatibles. The 486 has the equivalent of 1.2 million transistors compared to 275,000 in the Intel 386. There are 130,000 transistors in the 286 chip that's used in AT-style computers as compared to the 28,000 in the chip used in the original IBM PC.

The 486 not only processes data faster, but processes more data at a time. Comparing the 486 to an earlier-generation CPU is like comparing a race between a horse and a turtle. The horse not only runs faster, but its longer legs take it further with each stride. What's more, the 486 chip has a built-in math co-processor to speed up numerical calculations. With other Intel CPUs, the math co-processor is an extra cost item.

I placed the Positive 486 next to my 25 Mhz 386 system to compare their performance. My 386 is also a fast machine, but when it comes to raw processing power, the Positive 486 is more than twice as fast. One popular performance test, a program called System Information from Peter Norton Computing, clocked the machine's CPU at 54 times the speed of the original IBM PC, 12 times the speed of the original IBM AT and more than 1.5 times the speed of Compaq's 33 Mhz 386 machine.

But processor performance does not necessarily translate into faster computing. Using a 486 machine is like driving a high-performance sports car. It makes a difference on a race track, but not in normal driving.

For a real-world test, I ran several programs from my library on both machines. In every case the 486 was faster, but to see that speed, I had to create some rather ridiculous tests. On my 386 machine, it took 10 seconds for Microsoft Word for Windows to find and replace 982 characters in a file. The 486 did it in about 6 seconds. But in normal writing and editing, the extra power of the 486 had almost no impact on Word's performance.

Spreadsheet users who have very complex applications will notice a difference, but if you're like most users, you'll hardly see it. I have a Lotus 1-2-3 spreadsheet file that calculates a 30-year amortization schedule for a home loan. The 486 performed the calculation instantaneously. The 386 took about a second.

There are some applications where speed is critical. Some computer-aided design projects, for example, can take several minutes to re-draw a screen on a complicated drawing. There are scientific programs that take hours to run. Other uses for fast machines include software development, desktop publishing and multi-user database management systems. Finally, there are a lot of people who simply enjoy using a computer that's lightning fast, whether they need it or not. Satisfying that craving is now a lot more affordable.

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