The U.S. Patent and Trademark Office (USPTO) has initially rejected all 41 claims challenged by Nvidia in seven patents which Rambus has asserted in litigation against Nvidia.

Nvidia has challenged patent claims that stem from a complaint filed by Rambus in November 2008 against Nvidia in an International Trade Commission (ITC) action. The patents involve memory controllers related to graphics processors.

"We are pleased that the USPTO decided to review the patentability of Rambus' patents and agreed with Nvidia's challenge to all 41 claims," stated David Shannon, Nvidia executive vice president and general counsel. "We will continue to vigorously defend this matter in the ITC."

In addition to the seven patents reviewed thus far, two additional Rambus patents are subject to the same challenge by Nvidia and remain pending before the USPTO. A decision on the final two patents is expected in the next 60 days.