The suit, filed earlier this week in a U.S. District Court in Delaware, comes roughly three months afteragainst Intel for allegedly violating 11 of its patents.
The case centers on chips that are designed to be energy-efficient when not in use. Intel's countersuit alleges that Transmeta chips under the Crusoe, Efficeon and Efficeon 2 brands violate more than a half dozen of its patents.
Transmeta, meanwhile, claims that Intel's Core 2 Duo, in addition to processors dating as far back as its P6 line of chips, violates its patents that govern such tasks as slowing down a chip when not in use. Transmeta is one of the early pioneers of energy-efficient chips, filing some of its patents as far back as 1991--predating Intel's Pentium Pro.
Intel's countersuit was jointly filed with its response to Transmeta's initial lawsuit. In its response, Intel stated that it is not infringing on any "valid claims" relating to the 11 Transmeta patents. It also alleged that Transmeta's patents are "invalid" for failure to meet certain conditions of patentability.
"As expected, Intel has filed a timely response," said Greg Rose, a Transmeta spokesman, noting that the company is not able to comment until it has had a chance to review the cross-complaint.