Rambus has won another round in its SDRAM fight, signing up Toshiba to its contentious licensing fee for the memory technology.

Rambus called Toshiba its longest standing technology licensee in a statement confirming the agreement. It did not disclose financial terms.

The agreement is a victory for Rambus in its battle to force memory chip makers to pay for the use of its technology in mainstream SDRAM and DDR memory chips. Most memory chip makers have been fighting Rambus over the licensing scheme, arguing it did not disclose ownership of the patents when it was a member of a memory chip industry standards-making group.

Infineon led the revolt against Rambus in 2000, countersuing the company for allegedly using its influence with the standards group, the Joint Electron Devices Engineering Council, to purposefully design Rambus technology into the SDRAM standard with an eye for forcing companies to pay licensing fees.

Rambus ultimately won the suit, and has since sued a number of DRAM vendors for patent violations. In April, a California jury awarded Rambus $306.5 million in damages over a related patent suit against Hynix. The South Korean chip maker has appealed the ruling.

Rambus has drawn up a number of SDRAM licensing agreements since it won the US case, including a deal with Infineon. Infineon started paying Rambus $5.85 million per quarter last November. The payments will cease in November 2007 unless Rambus is able to sign licensing deals with the other SDRAM vendors. Rambus stands to gain an additional $100 million from Infineon if it signs up new licensees.

Toshiba is one of the world's premier memory chip producers, and already licenses a host of other Rambus technology, including patents related to XDR DRAM (high speed DRAM), DDR2 (double data rate, second generation), and various Rambus serial link interface designs.