Intel Files Suit Over Cyrix’s 486-SX Clone : * Technology: The firm claims infringement of four of its 386 chip patents. Cyrix has filed a countersuit.

Spooked by falling stock prices, Intel Corp. called Wall Street analysts and filed a suit Friday to knock a rival’s upcoming personal computer chip, the latest challenge to Intel.

Intel Vice President Tom Dunlap said the suit, which was filed in Dallas federal district court, accuses Cyrix Corp. of infringing on four Intel patents to create its 486-SX microprocessor clone.

The patents are related to Intel’s well-established 386 chip technology and not its more recent 486 line, said Dunlap, who is Intel’s general counsel.

Intel also received unofficial notice that Cyrix filed its own suit March 25, Dunlap said. In that suit, Cyrix says it did not violate the patents because it involved a third company in the chip’s manufacture. That company has a licensing agreement with Intel.

“Intel looks at this as a laundry. All they’re trying to do is pass this infringement through a laundry so it comes out clean,” Dunlap said.

The Intel suit came as no surprise. The company has traditionally defended its technology through the courts when other firms clone its products.

Earlier, Intel organized a teleconference to persuade analysts that Cyrix’s new chip won’t threaten Intel’s market share since it is just a souped-up version of the 386.

“Intel confirmed what we had already thought, that the Cyrix chip in question was not competitive with (Intel’s) 486,” said Tom Kurlak of Merrill Lynch & Co. in New York. “Sure, it’s an interesting product that will capture some of a niche market, but Intel’s main 486 engine won’t be threatened.”

Well, yes and no, said Michael Slater, editor of the respected Microprocessor Report newsletter. He said the Cyrix product, which is expected to be introduced Monday at the company’s Richardson, Tex., headquarters, is a fast “hybrid” that will likely do well.

The hardware of the microprocessor, which acts as the “brains” of PCs, is built like a 386-SX and fits into a 386-size socket inside a PC. But the chip acts like a 486-SX when it comes to performance.

Slater said software programs that measure “benchmark PC performance” levels show the Cyrix 486-SX is a 486-SX, although it has only a 16-bit “bus” like a 386. Intel’s 486 has a 32-bit bus. A bus refers to the internal wiring in a PC.

“I think you could argue either side, that the Cyrix chip is a 386 or a 486, depending on whichever one served your interests,” Slater said. “Cyrix wants to say it’s a 486 because it performs that way, and they want to leverage off the fact that Intel says the 486 is the future. Intel just wants to denigrate Cyrix’s product. I think Intel is a bit nervous.”

Slater added that Cyrix should have no trouble making a “true” 486 line of chips because it has mastered the basic microprocessor design.

Jim Chapman, vice president of marketing for Cyrix, said the company purposely built 486 attributes onto a 386-chip body in order to make a cheaper, smaller product and get it to market faster.

“Basically, its a 486 for a 386 price,” Chapman said. “Yes, I think Intel’s just nervous. We plan to be very competitive.”