LOS ALTOS, Calif. and HSINCHU, Taiwan – April 8, 2004 - Rambus Inc. (Nasdaq:RMBS), a leading developer of chip interface products and services, today announced that UMC (NYSE: UMC), a world leading semiconductor foundry, is now offering Rambus's RaSer^TM physical layer (PHY) cells for PCI Express^* applications to its foundry customers. This partnership gives chip developers access to cost-effective, high-performance PCI Express-based interfaces. Additionally, Taiwan-based XGI Technology Inc. is the first chip developer to license the new UMC RaSer PHY cell to drive its next generation PC graphics products.

"The PCI Express PHY is an important technology for next generation PCs," said Ken Liou, director of UMC's Design Support division. "As UMC continues to expand its IP offerings with an emphasis on interoperability and reusability, the Rambus PCI Express compliant RaSer core is a welcome addition to our portfolio. The combination of UMC's process technology and Rambus PHY IP enables chip developers like XGI to avoid costly R&D investments for PCI Express-based products."

Through the new licensing agreement, UMC’s customers can access Rambus's RaSer PHY. Rambus will provide complete characterization data and evaluation boards for any UMC-based testchips using the PHY cell. This Rambus RaSer PHY cell expands UMC's IP portfolio with additional PCI Express compatible capabilities.

"Desktop and mobile systems are moving to the PCI Express standard in order to achieve higher bandwidth and smaller form factors," said Chris Lin, president of XGI. “The Rambus RaSer interface reduces the silicon area and power of our graphics products, while exceeding the PCI Express electrical specification requirements."

The Rambus RaSer family of serial link cells is silicon-proven in 0.18-micron, 0.13-micron and 90-nanometer semiconductor process technologies. The RaSer PHY technology for PCI Express applications has been proven in systems and is in development now in leading PC chipset, graphics, communication switch and bridge chip applications.

"The PCI Express architecture is rapidly gaining market momentum, and RaSer PHYs are on the cutting edge of its deployment,"said Kevin Donnelly, vice president of the Logic Interface Division at Rambus. "By partnering with companies like UMC, Rambus will continue to enable mass adoption for advanced interface technology that results in faster, lower cost, more capable systems. Also, the availability of this offering helps customers get new capabilities to market faster."

In addition to the RaSer family of PHY cells, Rambus provides comprehensive engineering services to its customers. The availability of chip integration, package, test, and board and system characterization support help to ensure customers' success in the development and bring up of PCI Express chips and boards. Additional information on the RaSer family of serial link cells can be found at www.rambus.com/raser.

UMC (NYSE: UMC, TSE: 2303) is a leading global semiconductor foundry that manufactures advanced process ICs for applications spanning every major sector of the semiconductor industry. UMC delivers cutting-edge foundry technologies that enable sophisticated system-on-chip (SOC) designs, including 90nm copper, 0.13um copper, embedded DRAM, and mixed signal/RFCMOS. UMC is also a leader in 300mm manufacturing; Fab 12A in Taiwan is currently in volume production for a variety of customer products, while Singapore-based UMCi has just entered volume production. UMC employs over 8,500 people worldwide and has offices in Taiwan, Japan, Singapore, Europe, and the United States. UMC can be found on the web at http://www.umc.com.

Rambus is one of the world's leading providers of advanced chip-to-chip interface products and services. Since its founding in 1990, the company's innovations, breakthrough technologies and integration expertise have help industry-leading chip and system companies solve their most challenging and complex I/O problems and bring their products to market. Rambus's interface solutions can be found in numerous computing, consumer, and communications products and applications. Rambus is headquartered in Los Altos, California, with regional offices in the United States, Taiwan and Japan. Additional information is available at www.rambus.com.

XGI^TM Technology Inc., originated from eXtreme Graphics Innovation, was founded in June 2003 and is headquartered in Taipei, Taiwan. XGI^TM is a leading visual computing and GPU design company aiming to deliver a powerful and feature-packed GPU performance to enrich the users’ experience. XGI^TM has positioned itself as a Fabless IC design company. It offers a full range of video solution for Professional, Entertainment and now Mobile usage. For more detailed information, please visit XGI^TM website at http://www.xgitech.com.

Rambus and RaSer are registered trademarks of Rambus Inc. All other registered trademarks and other trademarks that may be mentioned in this release belong to their respective owners.

* PCI Express is a trademark of the PCI-SIG organization. Rambus and RaSer are registered trademarks of Rambus Inc. All other registered trademarks and other trademarks that may be mentioned in this release belong to their respective owners.

This release contains forward-looking statements that are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include statements about the adoption rate of the PCI Express interconnect into and suitability for the computing, consumer and communications markets, as well as the dates of when PCI Express-based systems are expected to ship into their respective markets. Additional forward-looking statements include the ability of Rambus RaSer cells to provide design flexibility in silicon proven process technologies as well as the adoption of these cells in leading PC chipset, graphics, and communication switch and bridge chip applications. These forward-looking statements are subject to risks and uncertainties, which could cause actual results to differ materially from those projected. Those risks include the possibility of reduced market adoption of the PCI Express interconnect protocol, the market response to these products, any delay in the development of Rambus-based products by licensees, any delay in the development and shipment of new Rambus products, any delay in the development and shipment of products compatible with Rambus products, a strong response of the market to competing technology, a failure to sign new contracts or maintain existing contracts for RaSer cell technologies, adverse litigation decisions and other factors that are described in our SEC filings including our 10-K and 10-Qs.