Rambus is dropping allegations against Nvidia relating to four of nine patents the IP chip firm claims are being infringed by GeForce graphics processors and nForce chipsets.
Nvidia says the withdrawal concedes the "weakness" of Rambus' claims, while Rambus says it's simply "streamlining" the process.
Rambus asked an administrative law judge at the US International Trade Commission to halt investigation on its claims, leaving five patents and 25 claims against Nvidia remaining.
The company launched its complaint against Nvidia with the ITC in November 2008. Rambus is asking the US trade authority to ban imports of Nvidia products using DDR (double data rate) memory controllers, which it alleges infringe on Rambus patents. The memory controllers are found in both Nvidia's chipsets and graphic chips, including GDDR3 memory used in the memory card maker's latest line of GPUs.
"We are pleased Rambus has recognized the weakness of these patents and claims, said David Shannon, Nvidia general counsel in a statement. "These withdrawals represent essentially half of the patents and one third of the claims asserted against us, and we look forward to address the remainder of the case."
Nvidia also claims Rambus has asked for termination of "several claims" from a fifth patent in the ITC action.
A Rambus spokeswoman, on the other hand, told El Reg that it filed the motion to "simplify the investigation, streamline the hearing, and conserve Commission resources in consideration of the evidence that will be presented at the hearing."
She went on to say that motions to terminate are fairly common in ITC proceedings and that Rambus choosing to drop the claims are completely unrelated to recent activity from the US Patent and Trademark Office.
Last week, the USPTO initially rejected 41 claims by Rambus stemming from seven of the nine same disputed patents. While the trademark office rulings aren't binding with the ITC, they are typically helpful in setting precedent.
The ITC hearing on the patent dispute is currently scheduled for August. ®