Rambus has sued Samsung, alleging the South Korean giant infringed its intellectual property rights by shipping DDR, DDR 2, GDDR 2 and GDDR 3 devices.

Rambus also brought one of a number of licensing agreements it has signed with Samsung to an early close, the memory technology developer said.

It claims Samsung has violated some 25 patents it holds. Many of them are among the list of patents it claims Hynix, Infineon, Inotera and Nanya also infringed. Those four memory makers were sued last January. Rambus' action against Samsung adds the South Korean company's name to the list of defendants in the January lawsuit.

Rambus was keen to stay friends with Samsung, which it described as a "valuable licensee of our patents". Samsung has licensed Rambus' RDRAM and XDR DRAM technologies.

Samsung had also licensed Rambus' SDRAM and DDR memory systems. That agreement was due to come to an end in less than a month's time, on 30 June. The timing of Rambus' legal assault suggests the two companies could not agree on a course of action when the licence was originally to have run its course. As Rambus CEO Harold Hughes put it: "A number of issues now exist that have made the renewal and expansion of the Samsung SDRAM/DDR licence difficult." ®

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