MOTHER BOARD

Here is a list of "things you should know" about upgrading your IBM or clone computer. I am going to focus on upgrading with a numeric co-processor, a math chip. And, whether or not you really need to upgrade to the latest 80486 system even if you think you are maxed out on your 33 Mhz 80386.

Even if you are familiar with the 80x87 series read on. Now there are alternative clone chips. One of these alternatives may just save you the expense of upgrading your whole motherboard or system .The thing that got me interested in this topic was a July 1990 Byte article reviewing two 25 Mhz 486 systems. The big news is that a 25 Mhz 486 CPU is no faster than a 33 Mhz 386 CPU. The only benefit that you get for spending thousands of extra dollars for the 486 system is that the 486's built-in floating point unit (FPU) is about twice as fast as the 33 Mhz 80387 (that you can add to your 386 system for about $550 to $600.)

If you are maxed out with your current combination you have several alternatives upgrading to a faster motherboard or even the 486 system. Now that I've told you what my thesis is, let me back up a bit and explain the basics. A "numeric co-processor" or "math chip" is an integrated circuit chip that you can plug into your motherboard. Its sole purpose is to speed up numeric calculations. This chip does calculations which would otherwise be done with software running on the CPU chip itself.

Numeric co-processors only benefit a small number of users because there are two conditions that must be met in order for these chips to make a difference. One is that a good portion of your computer time is spent doing mathematical calculations. The second is that the software doing these calculations must be smart enough to detect the presence of a co-processor and use it.

Computer Aided Design (CAD) programs such as AutoCad usually require a co-processor in order to get anywhere near acceptable response time. Lotus 1-2-3, QuickBasic, PageMaker and Ventura are other common programs that can take advantage of the co-processor. (Ventura and PageMaker only take advantage of it when printing graphics.) If you are running one of these programs, and you can ascertain that the program is "compute-bound" as opposed to "I/O-bound" (such determination is a whole science unto itself) then ask yourself if the computations are "number crunching" or "character crunching." If your application is compute-bound while doing mostly numeric calculations, then adding a numeric co-processor or upgrading to a faster alternative co-processor will allow your programs to run much faster. If you are compute- bound, but the application is just moving data around and not doing actual numeric calculations then a co-processor will NOT make it run faster.

One application where a co-processor is useless is a dedicated file-server. Although the 80486 CPU is now touted as "ideal" for file-servers, it is a waste of money for such an application. The extra money you spend for the 80486 is better spent on faster disk drives or more memory for buffers. File- servers don't use the floating point unit.

The claim to fame of the Intel 80486 CPU chip is that it has the numeric co-processor built-in. You don't need to add one. If you have an 8088, or an 80286 or an 80386, there is probably an empty chip socket on your computer's motherboard where you could plug in the co-processor. The part number of the co-processor depends on the part number of your CPU. The price depends on the speed (Mhz rating) and the chip maker.