The jury agreed with Rambus' claim that 10 of its patents had been violated, and awarded the firm infringement damages of $306.5m.
This figure represents compensation only for that portion of Hynix's SDRAM, DDR SDRAM and DDR2 memory products sold in the US.
The award does not yet include any pre-judgment interest, which is a typical element of damages that requires further consideration by the trial judge.
Rambus has also asked for permanent injunctive relief against Hynix to stop the manufacture, use, sale or import of infringing Hynix memory products.
The issue of an injunction will be addressed in future proceedings, currently expected to be convened this summer.
"We are very pleased with today's result, and very thankful for the considered attention of the jury and the court in this lengthy trial," said John Danforth, senior vice president and general counsel at Rambus.
In addition to the still pending Hynix case, Rambus has other patent cases pending against Micron, Samsung and Nanya addressing similar patent claims against similar products, as well as other issues.
Rambus also has a pending patent case against Micron, Samsung and Nanya addressing, among other things, more advanced patented technologies as used in more advanced memory products such as DDR2, GDDR2 and GDDR3.
In addition to these patent cases, Rambus has a pending antitrust case against Micron, Hynix and Samsung addressing issues that include an alleged joint boycott and the alleged use of an admitted criminal price fixing conspiracy between 1999 and 2002 to further that joint boycott.
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