Rambus said in such cases the patents remain valid and enforceable as originally issued until the reexamination proceedings are concluded, including all appeals. One study indicates that it takes up to six-and-a-half years for re-exam claims to work their way through the U.S. PTO, the spokesperson said. After that, the cases can be appealed to the Federal Circuit and possibly to the U.S. Supreme Court, Rambus said.

The ITC said in December 2008 it would investigate Nvidia and some Nvidia customers for possible infringement of Rambus patents, following a complaint filed by Rambus. In June, Rambus asked an administrative law judge at the ITC to terminate the investigation of Nvidia on four of the nine patents that Rambus initially claimed that Nvidia infringed.