Rambus did not unlawfully destroy documents in its patent dispute with Hynix, a US judge has decided.

Judge Ronald Whyte rejected a Hynix motion to dismiss Rambus' case - something that Rambus immediately and inevitably painted as a victory.

Rambus alleges that Hynix is using its patented memory technology without a licence. Hynix has countersued, arguing Rambus' patent claims are not valid. Whyte set a trial date of 6 March.

Hynix had argued that Rambus introduced a document destruction system at a time it knew a legal challenge was imminent in order to rid itself of damaging documents. But the judge disagreed and said that while Rambus destroyed some relevant documents, it had successfully established that "adequate similar and material documents or classes of documents were not destroyed". Rambus has produced some 1.2 million pages of documents in the case.

Memory patent legal battles are lengthy and ongoing. Rambus first took legal action against Infineon. A jury found Rambus had committed fraud by failing to disclose SDRAM patent but that verdict was later overturned on appeal.

Meanwhile, Hynix filed suit against Rambus. Meanwhile, Rambus is involved in other cases, having been sued by Micron, which also questions the validity of its patents, and the company also has been accused of unfair competition by the US Federal Trade Commission.

In another twist, Rambus sued Infineon, Micron, Hynix and Siemens, alleging they conspired to keep the price of Rambus' RDRAM memory technology high while the price of SDRAM was kept low so that RDRAM wouldn't take hold as a standard.

The memory companies deny that claim, but Infineon and Micron executives have pleaded guilty to conspiring to fix SDRAM prices in a separate investigation by the US Department of Justice.