Alpha: Shape of Chips to Come?

DIGITAL Equipment Corporation unveiled a microchip this week that puts it far ahead of its competitors - and at the center of an odd debate.

The chip, code-named "Alpha," should allow Digital to leapfrog its competitors. If the company can deliver the chip by July, as it promises, it will have the fastest microprocessor in the industry.

The Alpha chips eventually will work at up to 150 SPECmarks, a common benchmark of performance, although the initial chips won't be quite this fast. That performance handily beats any chip now on the market. Even Hewlett-Packard's newly announced microprocessor, to be available at the end of 1992, would run slower than Alpha.

Beyond this game of leapfrog lies a more fundamental question. What's the best way to design microprocessors? These all-important chips lie at the center of computers. The faster they are, the faster a computer runs. Companies have a choice of designs: RISC and CISC (pronounced "sisk"). A year ago, it looked as though superfast RISC chips would overrun the market. Now the industry isn't so sure.

"There was a big bubble of enthusiasm a year ago" for RISC, says David Smith, director of systems and software research at International Data Corporation, a market research firm.

But the price of RISC-based systems, often found on big desktop computers known as workstations, has not come down quickly, he says.

The result is that older CISC technology is likely to have a long life.

"You'll see a coexistence," says Dileep Bhandarkar, Digital's technical director for RISC systems. CISC machines will continue to run current software. "A lot of the new [software] applications will move to the RISC platforms."

If the computer industry were born today, it would undoubtedly move to RISC microprocessors. RISC stands for reduced instruction set computing. It means that the chip executes simple commands very rapidly. CISC, or complex instruction set computing, handles more complicated commands at a slower pace.

Even though it takes more commands to get a RISC chip to do the work of a CISC chip, the former still does it faster.

Digital is the latest company to move to RISC. Its venerable line of VAX minicomputers was based on a very complicated CISC architecture. Alpha is the company's first chip fully based on RISC technology. It runs 2-1/2 to three times as fast as a VAX.

"If you look out into the future, clearly RISC is the front-runner right now," Mr. Bhandarkar says. "But who knows what will come out 10 years from now?"

Despite the rise of RISC chips, CISC's future hasn't dimmed. It currently dominates the marketplace. Most personal computers run on CISC chips made by Intel Corporation. Other chipmakers, such as Advanced Micro Devices, are selling clones of Intel chips that are also popular with manufacturers of personal computers.

The CISC architecture used by Intel is much less complex than Digital's VAX line.

Far from ditching CISC technology, Intel is pouring millions of dollars to coax even more performance out of it. Later this year, the company says it will unveil the successor to its top-of-the-line 486 chip, the P5.

According to reports, Intel promises the P5 will run about twice as fast as its fastest 486 chip. Analysts suggest P5 will run faster. That could mean a speed of roughly 70 SPECmarks, Digital's Bhandarkar says.

That's comparable to today's RISC chips, but not close to the speeds promised by Digital or other makers of the next generation of RISC chips, which will appear by year-end.

As this race heats up, the distinctions between RISC and CISC will disappear, analysts say. Already, the lines between the two technologies are fuzzy. Analysts say that Intel's new P5 will take advantage of some RISC techniques to enhance its performance.

Performance alone won't determine which technology wins out.

Many analysts say that, barring a series of mistakes, Intel's market position will ensure continued strong sales. So much software for these machines is already in the hands of users that industry analysts doubt they will want to go to the trouble of converting their software applications to run on RISC.

"Intel is a big, big winner," says William Sines, an analyst with Technology Investment Strategies Corporation. "They have by all measurements the majority of the chips that are out there on computers. Intel has demonstrated that it will have technology that's close enough to RISC implementations."

"They don't have to be No. 1 in terms of the performance," adds Mr. Smith of International Data Corporation. Intel just has to stay near the top with a price that's competitive with RISC chips.