A US judge last week dismissed most of Rambus' patent claims against Korea's Hynix Semiconductor, one of the biggest memory manufacturers. Federal Judge Ronald Whyte of United States District Court for the Northern District of California found that Hynix didn't infringe the patents of Rambus in the manufacture of SDRAM and double data rate (DDR) DRAM memory products. The decision means that Rambus will not be able to charge royalties for these common types of memory. Any charges levied on manufacturers such as Hynix would have been passed on to consumers and businesses who buy the memory, either as separate components or in PCs. However, the judge also stayed the case until Rambus' parallel case against Infineon Technologies is resolved in a US appellate court is resolved. The judge in the Hynix case granted a Hynix request for a summary judgement based on a ruling last spring, which cleared German chip maker Infineon of patent infringement. The rulings mean that both Infineon and Hynix are now immune from Rambus patent-infringement lawsuits. But the situation could change again when a decision is reached on the Infineon-Rambus appeal, late next year or in 2003. Hynix, like Infineon, has also charged Rambus with fraud for failing to disclose its pending SDRAM patents to the JEDEC committee in 1993 to 1995, when Rambus participated in the design of the SDRAM standard. A jury in the Infineon case found that Rambus had committed fraud, but the California judge stayed Hynix's fraud case against Rambus. The case is part of an ongoing legal battle on which Rambus' future could hinge. Rambus memory was introduced as the exclusive memory type for Intel's Pentium 4 chip at the processor's launch, despite criticism that it is too expensive and several embarrassing glitches on Intel's part in adapting the chip to use Rambus memory. Once the future of Rambus' own RDRAM standard seemed less assured, the company began leveraging its patents to extract licence fees from companies producing SDRAM, the type of memory found in most personal computers. It also claims to be able to charge licence fees for manufacturing DDR SDRAM, an RDRAM competitor that is cheaper because it is based on the open SDRAM standard. Manufacturers hold the position that they should not have to pay licence fees for DDR and SDRAM because Rambus failed to disclose that it had already applied for patents covering these technologies when the standards were being developed. See Chips Central for the latest headlines on processors and semiconductors. To find out more about the computers and hardware that these chips are being used in, see ZDNET UK's Hardware News Section. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Chips Central forum Let the editors know what you think in the Mailroom. And read other letters.