Pentium III is more like Pentium 2.1

by Alan Zisman (c) 1999. First published in Canadian Computers Wholesaler, March 1999

The changeover from Intel?s original Pentium to its next-generation Pentium-II models was a big one, one that in many ways, the industry still hasn?t completed.

While Intel has abandoned the Pentium (and Pentium-MMX) Socket 7 design, it remains in use by Intel?s competitors?and one of those competing Socket 7 CPUs, AMD?s K6 model line, powered the most computers sold at retail last year?out-selling any of Intel?s models.

But in bringing out the Pentium-II design, Intel tried to push the industry to adopt the company?s proprietary Slot One design?putting the processor, its cache RAM, and its support chips onto a large cartridge. Even Intel?s low-end model: Celeron, adhered to the Slot One standard, requiring all-new motherboard designs.

P-II designs also came with Accelerated Graphics Port (AGP) video, though that?s now available on a few, high-end Socket 7 boards. And most recently, they?ve pushed the system bus up from 66 MHz to 100 MHz.

But it?s the end of the road for the P-II series. Intel has announced the Pentium-III, which should be shipping as you read this. But don?t expect anywhere near as traumatic a transition as last time around. In fact, I doubt that the new product line is really deserving such a dramatic renaming.

If we think of Windows 95 as Windows 4.0?a major break from its Windows 3.1 predecessor, then last year?s Win98 would have been Win 4.1. Similarly, the Pentium-II design was a major break from its Pentium predecessor, but the P-III is more like a Point-one upgrade.

Unlike the drastic design changes necessitated to handle the P-II, the new models are slot-compatible. They will continue to use the Intel 440BX motherboard chipsets used by the current generation of P-II designs. (Users wanting to upgrade current P-II systems will need to upgrade their system Bios, however?so don?t expect to simply pop a new P-III into an existing P-II computer. CPU speeds will, at least initially, not be much, if any faster than high-end P-IIs, with 450 MHz and 500 MHz models replacing 400 and 450 MHz P-IIs?and continuing to run on a 100 MHz system bus.

In fact, there will be only one major difference between a 450 MHz P-II and a 450 MHz P-III. The newer CPU includes what Intel formerly code-named the Katmai New Instruction set?a collection of 70 new low-level processor instructions, designed to improve multimedia performance and more. Katmai is targetted at voice recognition, streaming video, and improved floating point computation.

Sounds like MMX, doesn?t it? MMX, appearing in early 1997, was also a group of new processor instructions, aiming at bettering multimedia performance. MMX was first added to Pentium-level processors, with compatible instruction sets soon appearing in most of the Pentium-clone processors as well.

In retrospect, MMX was less than a revolution, its performance improvements more promise than reality. The problem was that software had to be specifically coded to take advantage of MMX features, and with a few exceptions, not much was. Even game companies have been more likely to produce versions optimized for various 3D add-on cards than to write MMX-specific versions.

Will the same fate await the Katmai instructions? We?ll have to wait and see. Microsoft has promised to build support for Katmai into its upcoming Windows 2000 operating system. But unlike MMX, Intel?s competitors seem self-confident enough to go their own route?a non-compatible set of new processor instructions being called ?3D Now!?.

Whether Katmai turns out to matter or not, P-III based systems will rapidly become available, mostly because they require such minor changes from existing P-II systems.

And the P-III is clearly the direction that Intel foresees  for mainstream systems, at least for the next little while. Intel?s Greg Welch, brand manager for the P-III claims that with the P-III?s release, there will be no new versions of its predecessor.

And expect design changes in the future, to support upcoming, faster P-III models. Look forward to a 133 MHz bus speed, later in 1999, requiring new chipsets, in the opinion of Ming Chok, vice president of motherboard manufacturer Soyo. There will also be a sped-up 4x version of AGP, again requiring system revisions. CPU speeds should reach 600 MHz late this year.

At the same time, Intel is planning to revise and simplify the Slot One design for P-IIIs towards the end of the year, according to the company?s Paul Otellini, executive vice president of the Intel architecture business group. All these changes will mean that later P-III models will no longer be compatible with current systems?but the pace of change will be more gradual than we?ve seen in the recent past.

In fact, Otellini suggested, Intel is hoping that system designs and motherboard chipsets will be able to last over two generations of processors?responding to complaints from manufacturers forced to too quickly change their product lines.

Ironically, while Intel is trying to slow the sometimes frantic pace of change, competitor AMD, which has been successfully building more and more powerful processors compatible with the older Socket 7 designs is trying to achieve a dramatic break with its past.

While its new and improved 450 MHz K6-3 remains a Socket 7 model, it appears to be the end of that evolutionary pathway. The upcoming K7 series will use a Slot One-like technology to run at 500 MHz and above, with the company aiming for speeds as high as 1000 MHz sometime in 2000, as the company switches from aluminum to copper technology. The initial K7s, announced last October and due mid-1999, are expected to run on an innovative 200 MHz system bus, built using Digital?s advanced Alpha EV6 bus technology. While this will certainly provide real performance improvements, the pressure will be on AMD to convince system manufacturers to build motherboards and systems based on it.

The result will be Intel and AMD switching roles, with Intel offering systems only slowly evolving from current standards while promising only modest performance improvements. AMD, on the other hand, is taking over Intel?s traditional role of promising dramatic performance improvements to manufacturers willing to make an equally dramatic break with current designs.