A FEW WEEKS ago, I mentioned that buying a PC was getting complicated because there were so many versions of Intel's Pentium processor floating around.
That brought e-mail from a reader who said that if this was so complicated, maybe I should explain it. So here's a little primer to help you understand the stuff you see in the advertisements.
First things first. The microprocessor is the heart of your computer. It's an impossibly complicated chip with millions of transistors and integrated circuits that does all the real computing. The type of processor you have determines what kind of software will run on your machine and how fast that software will run.
Between 85 and 90 percent of the desktop computers sold today use some variant of Intel's Pentium processor or a compatible chip. The rest use a PowerPC chip developed jointly by Apple, IBM and Motorola. Most of those are in Power Macintoshes.
In addition to the name of the chip, you'll see a speed designator measured in megahertz, or millions of cycles per second. This refers to the speed of the clock that governs the chip's operations. It takes one cycle to process a simple instruction, so theoretically, the higher the number of Megahertz, the faster the computer. Typically, you'll see something like "Pentium 200 mhz" in advertisements, which means a Pentium chip running at 200 million cycles per second.
So what does Pentium mean? Well, it's a concocted, pseudo-Greek thing that has to do with the number five. Intel coined the term back in 1993 when it introduced its fifth-generation processor. Before that, the company designated its chips with numbers such as 80386 or 80486. But Intel changed its strategy after competitors started using the same designations and the courts ruled -- with good reason -- that Intel couldn't trademark a number.
In any case, the Pentium marked a significant improvement on older Intel processors, and for a couple of years it was the only choice most Intel buyers had. It comes in a variety of clock speeds ranging from 75 to 200 mHz. You'll still find a few computers with plain old Pentium processors on the shelves, mostly in laptops or desktop closeouts. For basic business applications the original Pentium is still an acceptable choice, particularly if you're on a limited budget.
If you're interested in high speed graphics, digital photography, games, videoconferencing or multimedia programs, look for one of the new Pentium MMX processors. The MMX design, unveiled in January, incorporates the first major change in Intel's chip logic since the late 1980s. It adds 57 internal instructions designed to speed up video, graphics and sound operations. You may still pay a small premium for a Pentium with MMX, but not much, because the chip has quickly become the standard in computers designed for home and small office applications.
The catch with Pentium MMX machines is that software must be specifically designed to use those new instructions. Existing software won't run any faster, and for the next few years, most multimedia programs will probably come with dual code for the standard Pentiums and MMX processors. So there's no need to trade in your existing computer for a new MMX model unless you're dying to play Virtual Kick 'n Punch in all its enhanced bloody splendor.
But if you're looking for a home or office PC today, the 200 mHz Pentium with MMX offers the biggest bang for the buck.
Now it gets complicated. Let's wind the clock back a bit to 1996, when Intel introduced a processor called the Pentium Pro. This was an advanced redesign of the original Pentium aimed at the corporate and server market. The Pentium Pro was specifically engineered to run sophisticated 32-bit programs and operating systems such as Windows 95 and Windows NT.
It does that very well, and it's definitely the chip of choice for high-speed computers that use more than one processor.
While Intel would be delighted to sell you a Pentium Pro at a premium price, the company is quite up front about the fact that it's aimed at the business market. In fact, for most users the Pentium Pro is a bad choice because it actually runs older Windows programs more slowly than the regular Pentium chip.
It doesn't have MMX technology, either, so it can't take advantage of new multimedia programs.
All of which brings us to Intel's newest offering, the Pentium II. This is essentially a Pentium Pro with MMX technology. It brings all of Intel's design improvements together into one chip. There are no slow versions of this barn burner -- your choices are 233, 266 and 300 mHz.
The Pentium II has also been physically redesigned, which means that computer makers have to design new circuit boards to accommodate it.
All of this makes the Pentium II a bit pricey for the home market (figure $500 to $1,000 more than the Pentium MMX). But if you want state-of-the art, this is it.
If you're looking for top performance at a bargain price, you may be able to find it soon with a new chip from one of Intel's competitors, Advanced Micro Devices Inc.
According to various testers, AMD's new, compatible K-6 processor is on a par with the Pentium II but a couple of hundred dollars cheaper. And unlike the Pentium II, it will fit today's standard computer designs.
Look for the K-6 first in lesser-known brands of computers, but eventually you're likely to find it in mainstream machines.
You can reach the author by sending e-mail to mike.himowitaltsun.com.
Pub Date: 6/29/97