What you should know about 486 processors before buying a new PC

By Zatni Arbi

JAKARTA (JP): First and foremost: All 486 CPUs are equal, but some are more equal than others! That's exactly what most computer salespeople don't want you to know.

I happen to be involved in a committee that handles this year's PC procurements for the office where I work. We have requested interested parties to submit their bids, which should include the specifications and price lists of the machines they are offering. When reading the specification sheets that we received, I was really surprised to see how unclear they were.

This reminded me of a friend who had bought a new 486 machine more than a year ago. He had chosen a 486 based on a very general recommendation that I had given him. I was saying, at that time, that everybody should be buying 486 for their own use and leave the 386 for use by students in computer classes. My recommendation turned out to be too general to be of real use. The computer store sold him a machine with a 486SLC CPU, which is more suitable to laptops or notebooks.

While the 486SLC was a 486, indeed, the processor speed was not up to the requirements of current Windows applications. So, when I came to his place to see his new computer, I realized that I had given him an incomplete advice, and that had just made him vulnerable to unscrupulous salespeople.

It seems that PC salespeople deliberately give obscure specifications. For instance, what do you know when the specifications they have given you is the following "Processor, 80486, 33 MHz"? Is it a DX? Is it an SX? You can't tell. Yet that is what they tend to give you.

Boosted price

Those of us who know the PC industry in this country fairly well will perhaps agree that people are always trying to make additional profits by lowering the standards and reducing the specifications of the PCs that they sell, all without the knowledge of the unsuspecting customers. On the other hand, if the products they carry have a new feature, such as "Local Bus", "Green" or "EPA Certified", they will overemphasize it to justify a boosted price.

So, here's in a very general terms what you should know about 80486 processors (or CPUs). First, there are at least four manufacturers of 80486 chips whose products can be found in general market: AMD, Cyrix, IBM, and Intel.

In general, you shouldn't worry about compatibility, although the chips from Cyrix have been reported to have some bugs (more on this later). These chips had undergone thousands of tests before they went into mass production to ensure compatibility with industry standards from Intel.

The suffix DX indicates presence of a built-in math co- processor. A CPU with the SX suffix doesn't have it. If you go with Intel products, choose a DX that runs at least at the speed of 33 MHz (I said this in one of my previous articles a couple of months ago, and it's still valid). You may not immediately need the built-in math co-processor in the DX class, but with such a small difference in price between a 486SX 33 MHz and its DX counterpart, it's nice to have it available in case you do need it.

If you decide to use AMD or Cyrix, the same is true. Choose at least the one with the clock speed of 33 MHz. Unfortunately, however, instead of using the SX suffix for CPU chips that have no built-in math co-processor, Cyrix use the suffix SLC/e. You have to be careful, as Intel also has an SL variety that is fully compatible with 486DX -- only with less power consumption. Don't confuse SLC with SL. SLC CPUs are intended for use in portable computers rather than for desktops.

We already have a great number of species of CPUs on the market, far too many, and yet new ones are appearing weekly. Even right now we already have AMD 486DX2 available here in Jakarta (in fact, I have just tried one out and I'll give you my report soon). Furthermore, as I have also reported, Intel has just started shipping its clock-tripled version of the 80486 family, which is called, anomalously, iDX4!

Upgradable?

The possibility to upgrade your processor to a faster one, for instance from 486DX 33 MHz to 486DX/2 66 MHz, is exactly another feature that is touted much too often in persuading a computer buyer to buy a particular model of PC.

In reality, upgradability does not mean anything. The new replacement chip will still be expensive, and you'll be asking yourself, "What am I going to do with the old chip?" Furthermore, by the time you really need a faster machine you'll be considering buying a new system instead of just a processor chip, since you'll also need faster and more sophisticated components as well. So, my advice is, don't pay extra for upgradability which you're not going to need anyway.

About Cyrix

According to this month's Windows Magazine, a bug was found in Cyrix's Cx486DX chip that could cause troubles if you're running applications for 32 bit operating systems, such as OS/2 and Windows NT.

So, until the bug is ironed out, high-end systems that run such operating systems should probably not use this chip. However, if you're just running 16 bit applications for Windows 3.1, this chip is OK. It is also reported that the bug does not affect other Cyrix processors.