The ruling, protecting Intel's control of the 'microcode' for the 486, represents a blow to its chief rival in the market, Advanced Micro Systems, a Silicon Valley chip cloner.
Advanced Micro had developed its own version of the popular 486 using Intel's chip software, and was ready to start shipping the product to computer makers by the end of the year.
Advanced Micro has used Intel microcodes since 1976, when it signed a licensing agreement with the industry leader, and last year sold more than 2 million 386 chips employing Intel's programming. While its 1991 sales were only an eighth of those of Intel, AMD's sales were expected to triple this year.
The plummeting price of personal computers has spurred demand for the top-of-the-line 486 chip, which is believed to earn Intel profit margins of more than 75 per cent. Intel expects sales of the 486 to top dollars 1.7bn ( pounds 1.1bn) this year.
Advanced Micro, its closest potential challenger in the 486 market, will not have another model ready for delivery until mid-1993, and it is not clear whether the new version will overcome the copyright ruling. Industry analysts estimate the lost revenue to be in the hundreds of millions of dollars.
Cyrix Corp, a Texas chip maker, is now likely to be the first manufacturer to come out with a compatible 486 rival.Reuse content