LOS ALTOS, Calif. and HSINCHU, Taiwan - August 23, 2005 - Rambus Inc. (Nasdaq: RMBS), one of the world's premier technology licensing companies specializing in high-speed chip interfaces and UMC, a world leading semiconductor foundry (NYSE: UMC, TAIEX: 2303), today announced that they have extended the availability of Rambus's patented PCI Express* PHY cells to UMC's 180nm, 150nm, and 90nm processes. This development expands on the existing 130nm licensing agreement between the two companies, which was signed in 2004.

Under the agreement, UMC foundry customers gain access to Rambus's broad portfolio of PCI Express-based interfaces. The Rambus PCI Express PHY cells have been designed to provide chip developers with a solution that optimizes link utilization, latency, power consumption and silicon footprint. The PCI Express interface standard is one of the industry's most successful for chip-to-chip interconnects and can be found in system applications ranging from supercomputers to PCs and digital TVs.

UMC customers currently in production with Rambus's PCI Express PHY cells include the high-volume PC chipset manufacturers ULi Electronics and the high-volume PC graphics manufacturer XGI Technology, Inc. Rambus PCI Express PHY cells are also in production in various bridge and communication IC products based on the UMC foundry process. "By partnering with UMC, Rambus continues to enable mass adoption for advanced interface technology that results in faster, lower cost, and more capable systems," said Laura Stark, vice president of Rambus's Platform Solutions Group. "In addition, the availability of this combined offering helps chip and system developers bring new capabilities to market with lower risk."

"We are pleased to expand our licensing agreement with Rambus to make its proven IP solutions available to a broader range of technologies, including our mainstream 90nm process," said Ken Liou, director of UMC's IP and Design Support Division. "This agreement allows our customers designing SoCs targeting PCI Express applications to benefit from Rambus's broad offering of PCI Express PHY cells."

Rambus PCI Express PHYs are complete serial communication cells optimized for implementing the physical layer of the PCI Express standard. The silicon-proven serial interfaces feature point-to-point, full duplex signaling and support up to a 3.2Gbps data rate. Rambus has also demonstrated its Turbo PCI Express platform with serial links operating at 5.0Gbps and 6.25Gbps data rates to meet future PCI Express requirements. Rambus PCI Express PHYs are listed on the PCI-SIG Integrators List, having passed PCI-SIG compliance and interoperability testing by Rambus PHY cell customers and digital controller partners. The PCI-SIG is the special interest group that owns and manages PCI specifications as open industry standards. The Rambus PCI Express PHY cells are supported by a comprehensive suite of digital controllers and support services to provide chip developers with a complete system solution. For more information on Rambus's broad PCI Express offering, visit www.rambus.com/products/pciexpress.

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, and mixed signal/RFCMOS. UMC is also a leader in 300mm manufacturing; Fab 12A in Taiwan and Singapore-based UMC are both in volume production for a variety of customer products. UMC employs over 10,500 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 premier technology licensing companies specializing in the invention and design of high-speed chip interfaces. Since its founding in 1990, the company's innovations, breakthrough technologies and integration expertise have helped 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 Chapel Hill, North Carolina; Bangalore, India; Taipei, Taiwan; and Tokyo, Japan. Additional information is available at www.rambus.com.

Some of the statements in the foregoing announcement are forward looking within the meaning of the U.S. Federal Securities laws, including statements about future outsourcing, wafer capacity, technologies, business relationships and market conditions. Investors are cautioned that actual events and results could differ materially from these statements as a result of a variety of factors, including conditions in the overall semiconductor market and economy; acceptance and demand for products from UMC; and technological and development risks.

* PCI Express is a trademark of PCI-SIG; Rambus and the Rambus logo are registered trademarks of Rambus Inc. All other service marks, trademarks, or registered trademarks of their respective owners.