Rambus Inc. (RMBS), a designer of high-speed computer-chip interfaces, won a $306.5 million jury verdict Monday in its patent-infringement lawsuit against South Korea's Hynix Semiconductor Inc., company officials said.

Shares of Rambus rose $5.13, or 13.3 percent, to $43.73, after being halted earlier on the Nasdaq Stock Market.

Jurors in the monthlong trial decided that all 10 Rambus patent claims were valid.

The patents involved technology known as dynamic random access memory, which increases the speed of memory in computer chips, along with several related technologies.

"We are very pleased with today's result," John Danforth, the company's lawyer, said in a release. He vowed to continue seeking compensation for the company's patented inventions.

The verdict, returned by a jury in federal court in San Jose, is the latest victory in Rambus' six-year battle to assert patents against a host of companies that sell memory chips used in personal computers and other electronic devices.

The Los Altos-based company has similar suits pending against Micron Technology Inc. (MU) of Boise, Idaho, South Korea's Samsung Electronics Co. and Taiwan's Nanya Technology. Rambus also has filed antitrust suits against those three companies.

In August 2000, Hynix sued Rambus in an effort to have 11 of its patents declared invalid. Rambus countersued, saying Hynix's use of the technology infringed upon its patents and succeeded in getting the case expanded to include 14 patents.

In pretrial proceedings, U.S. District Judge Ronald Whyte ruled that Hynix infringed on some Rambus patents and ordered the parties to try the remaining claims before a jury.

On Monday, Rambus said the award represents compensation only for Hynix's SDRAM, DDR SDRAM and DDR2 memory products sold in the United States, and covered Hynix sales between June 2000 and the end of 2005.

Rambus also has asked for a permanent injunction against Hynix to stop its manufacture, use, sale, or import of Hynix memory products.

That request isn't likely to be decided until after a third phase of the case addressing Hynix counterclaims is tried this summer, the company said.

Such Hynix counterclaims include challenges to the enforceability of Rambus patents and allegations that Rambus impeded market adoption of DDR SDRAM.

Not all Rambus patent battles have gone well for the company.

In March 2005, infringement claims against Infineon Technologies AG (IFX) were dismissed after a federal judge in Richmond, Va., learned that Rambus destroyed documents in anticipation of the case.

The two companies settled a few weeks later, with Infineon agreeing to pay Rambus a quarterly license fee of $5.85 million through 2007.