Encouraged by Digital Equipment Corp’s audacious challenge to Intel Corp on Tuesday (CI No 3,160), Cyrix Corp has now also filed suit against Intel Corp for patent infringement, in the US District Court for the Eastern District of Texas. Cyrix – which has quite a history of legal tussels with Intel under its belt already, asserts that Intel products including the Pentium, Pentium Pro and Pentium II microprocessors, infringe on one or both of the patents issued to Cyrix on May 13 1997, and is seeking preliminary and permanent injunctive relief along with unspecified damages and fees. The patents relate to power management and register renaming. Cyrix, and its rival Advanced Micro Devices Inc, spent years battling Intel over the rights to clone the Intel architecture, the tide turning in favor of the clonemkers during 1994 (CI No 2,348) when most of the patent disputes were settled. Cyrix and Intel have only just settled their latest quarrel, over the use of Intel’s MMX technology (CI No 3,131). Cyrix recently won the endorsement of Compaq Computer Corp, which is using the MediaGX processor in its Presario 2000 series of home computers. The company insisted that the timing of the suit was coincidental. Meantime, Intel Corp flatly rejected DEC’s patent infringement claims, In a statement released yesterday it said Based on a preliminary analsysis of of the claims, Intel does not believe any of its products infringe on patents asserted by DEC. Intel says it will vigorously defend itself against the suit, but so far, has not counter-sued DEC as is usual in these kinds of cases.