Advanced Micro Devices has fired off a federal antitrust lawsuit against Intel, claiming that its rival has a monopolistic grip on the PC industry.

The suit, filed Monday in the U.S. District Court in Delaware, details alleged scare tactics and coercion that AMD claims Intel imposed on 38 companies, including large-scale computer makers, small system builders, wholesale distributors and retailers.

Intel processors account for more than 80 percent of the computers running x86-based chips, according to IDC. Those chips run many families of operating systems, including Microsoft Windows, Solaris and Linux. Even Apple Computer has announced that it will switch exclusively to x86 processors for running Mac OS software, beginning in 2006.

Intel's business practices will come under the microscope in the coming months, and not for the first time. But has it done anything wrong?

Coercion or circumstance — that's the big question in the antitrust case filed by AMD against Intel.

The suit, filed late on Monday, provides a fairly detailed and lengthy laundry list of alleged misdeeds by Intel. The complaint alleges that in 2002, for instance, Intel agreed to pay NEC more than ¥300m (£1.5m) per quarter in exchange for caps on purchasing from AMD. AMD's share of NEC's consumer business went from 84 percent to virtually zero in six months, the complaint says. It also states that NEC constrained sales efforts around Opteron-based servers.