Updates to this story
The US Patent and Trademark Office has ruled that Nvidia infringed one Rambus patent but rejected another infringement.
Rambus, which is strong on intellectual property rights to the points of obsession, had claimed that Nvidia had infringed three of its patents so it's something of a mixed result.
Rambus has had a long history of litigation with Nvidia - last June it withdrew a request to the US International Trade Commission (ITC) to investigate nine patents. Instead, it substituted a claim that Nvidia had infringed other patents.
A year before that, Rambus had claimed that Nvidia breached 17 patents. The ITC is still investigating claims against the three patents that the USPTO ruled on yesterday.
Rambus, meanwhile, is still involved in other legal cases. According to the Wall Street Journal, Nvidia will appeal against the USPTO ruling.