Intel was hit with a lawsuit by the Wisconsin Alumni Research Foundation this week, alleging that the chip maker used a WARF invention in its processor architectures, including the popular Core 2 Duo.

The patent infringement lawsuit, filed in U.S. District Court for the Western District of Wisconsin, alleges that Intel implemented in many of its chips a University of Wisconsin, Madison, invention of a circuit that executes instructions to speed up processor performance.

The patent, titled "Table based data speculation circuit for parallel processing computer," was awarded to four university researchers in 1998.

WARF is looking for an undisclosed amount of compensation from Intel and an order for the company to stop selling certain processors, including the Core 2 Duo. A court date for legal proceedings has not been set yet, said Janet Kelly, communications director for WARF.

WARF is not a part of the University of Wisconsin, Madison, but a private organization that patents and licenses inventions of the university, Kelly said.

Intel has refused to enter into a license agreement with WARF related to the patent, according to court documents. WARF said had made repeated attempts to offer Intel legal licensing opportunities for the technology.

The suit came as a surprise to Intel.

"We were in discussions with WARF for more than a year on this issue. However [we] did not expect this suit," Intel spokesman Chuck Mulloy said.

Intel is evaluating the complaint and will file a response, he said.