Intel introduces fastest version yet of i486 chip -- about 25% more speed


The Intel Corp., which makes the microprocessors that are the core of tens of millions of PC-compatible personal computers, has delayed its introduction of a next-generation microprocessor until next year. The chip, code-named the P5, is intended to be the successor to Intel's popular i386 and i486 processors.

Intel softened the disappointing news last week by introducing the fastest version yet of its i486 chip. The new i486 DX2-66 chip uses Intel's so-called clock-doubling technology to achieve speeds of 66 megahertz, or 66 million cycles a second. The previous speed record for Intel's i486 chip was 50 megahertz.

From the humble vantage point of human speed, where typing 60 words a minute is considered swift, the difference between 50 million cycles a second and 66 million might seem silly. Still, to computer users who demand the fastest available processors for jobs like searching through big data base files, the extra 15 million cycles are important because they represent about 25 percent more speed than the fastest PC's today.

The actual gain will depend on many other factors, like the type of software, the amount and type of memory the computer has and the speed of the various components attached to the computer. In general, though, the user of a i486 DX2-66 chip will spend fewer minutes each day waiting for the computer to finish its job.

Purists will note that the i486 DX2-66 chip is not a "true" 66 megahertz chip. To the computer, the new chip looks like Intel's 33-megahertz i486 DX chip.

If there were a clock on the outside of the chip, the hands of the clock would appear to move at a normal rate. Inside the chip, however, the clock's hands would spin at twice the speed.

The chip operates at double time as long as the special high-speed memory circuits attached to the processor keep feeding data to the parts that do the calculating.

Whenever the chip's data pipeline empties, which happens when the computer has to grab data from memory chips, a hard disk or some other part of the system, the chip reverts to its 33-megahertz speed.

A "true" 66-MHz chip, on the other hand, would maintain a steady pace. Intel makes a true 50-megahertz i486, but it costs quite a bit more than the "pseudo-50" DX2 i486, which is a clock-doubled 25. Intel has not released a "true" 66-MHz i486.

Many of the leading computer companies have already started selling computers based on the 66-MHz i486 DX2 chip, including Advanced Logic Research Inc. of Irvine, Calif., the Compaq Computer Corp. of Houston, the Dell Computer Corp. of Austin, Texas, the International Business Machines Corp. of Armonk, N.Y., and the Tandy Corp. of Fort Worth, Texas.

Compaq is widely credited with starting the current price war in the computer industry, so it quickly became the reference point for these new 66-MHz speedsters.

The Compaq Deskpro 66i, which uses the i486 DX2-66 chip, has a list price of $2,749. The computer comes with the DOS operating system, 120 megabytes of hard disk storage, four megabytes of system memory, a special graphics controller that makes Windows operate much faster, a 3.5-inch diskette drive, Compaq's Business Audio sound system, and three standard expansion slots, but no monitor or keyboard.

Compaq's price was instantly undercut by ALR, Dell and others. Dell, for example, offers the Dell 486P/66 for $2,499. It has all of the features of the Compaq machine except the Business Audio, plus a color monitor and keyboard.

Compaq may also have been indirectly responsible for the delay in Intel's forthcoming P5 chip.

By starting the industry price war, Compaq had a hand in driving down prices for all computers. People who had planned to spend $3,000 for a 386-based PC suddenly found that they could get a more-powerful i486 computer for the same money. And because demand for these i486-based machines has been so high, there may have been less urgency on Intel's part to get the P5 to market.

In any event, Intel now says it will introduce the P5 chip by March.

The P5 chip, which may or may not be renamed the i586, is Intel's most ambitious chip design yet, with more than 3 million transistors squeezed into a space not much larger than a postage stamp.

In contrast to the 66-megahertz i486 DX2, which is today's fastest PC chip, Intel officials said the P5 chip's slowest speed would be 66 MHz. According to some reports, Intel expects the 66-MHz P5 to zoom through applications in half the time needed by the 66-MHz i486 DX2.

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