Rambus Inc. (NASDAQ: RMBS) today announced the closing of its previously announced public offering of $150 million aggregate principal amount of 5% Convertible Senior Notes due 2014. Rambus has also granted the underwriters an option to purchase up to an additional $22.5 million aggregate principal amount of the notes to cover over-allotments, which has not been exercised to date.

The notes are unsecured, unsubordinated obligations of Rambus and interest is payable semi-annually at a rate of 5% per annum. The notes mature on June 15, 2014, unless earlier repurchased, redeemed or converted. Prior to March 15, 2014, the notes are convertible only upon specified events and, thereafter until maturity, at any time. Upon conversion, the notes will be settled by the payment of cash up to the principal amount of the notes and, with respect to any excess conversion value, by delivery of shares of Rambus’ common stock. The notes have an initial conversion rate of 51.8000 shares of Rambus’ common stock per $1000 principal amount of notes, which is equivalent to an initial conversion price of approximately $19.31 per share of common stock, subject to adjustment in certain circumstances. The initial conversion price represents a conversion premium of approximately 30% relative to the last reported sale price of the common stock of $14.85 per share on June 23, 2009. Rambus has the right to redeem the notes in whole or in part at a specified redemption price at any time on or after June 15, 2012 if certain conditions are met.

Rambus intends to use the net proceeds from the offering for general corporate purposes, which may include financing potential acquisitions and strategic transactions, repayment of Rambus’ zero coupon convertible senior notes due 2010, and working capital.

Credit Suisse Securities (USA) LLC and J.P. Morgan Securities Inc. were the joint book-running managers for the offering.

Rambus has filed a registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and the other documents Rambus has filed with the SEC and which are incorporated by reference in the prospectus for more complete information about Rambus and this offering. Copies of the prospectus may be obtained from Credit Suisse Securities (USA) LLC, Prospectus Department, One Madison Avenue, New York, NY 10010, or J.P. Morgan Securities Inc., 4 Chase Metrotech Center, CS Level, Brooklyn, NY 11425 Attention: Chase Distribution & Support Service Northeast Statement Processing.