Chipmaker Rambus (RMBS) late Monday topped its revenue forecast for the second quarter. Rambus stock rose in extended trading.The San Jose, Calif.-based company earned 53 cents per share on sales of $172.2 million in the June quarter. Rambus had guided to second-quarter revenue of $170 million, based on the midpoint of its outlook from three months ago. On a year-over-year basis, Rambus earnings increased 61% while sales rose 30%.↑ XNOW PLAYING Big Tech Blitz: Key Reports From Microsoft, Meta And Amazon Will Reveal AI Monetization EffortsComplicating matters for investors, Rambus reports results using generally accepted accounting principles, or GAAP, while most analysts use non-GAAP figures for sales and earnings. And Rambus doesn't explicitly report non-GAAP figures in its earnings news release.Analysts polled by FactSet had expected Rambus to earn an adjusted 58 cents a share on adjusted sales of $167 million in Q2.For the current quarter, Rambus predicted revenue of $175 million based on the midpoint of its guidance. In the third quarter last year, Rambus posted sales of $145.5 million.In after-hours trading on the stock market today, Rambus stock advanced more than 5% to 67.69. During the regular session Monday, Rambus stock climbed 2.2% to close at 64.24.Rambus makes memory interface chips. Its high-performance memory subsystems alleviate the bottleneck between memory and processing for data-intensive systems, including artificial intelligence applications. It generates revenue from product sales, royalties and other means."Rambus delivered a very strong Q2, with record product revenue and record cash generation reflecting the strength of our business model and execution," Chief Executive Luc Seraphin said in a news release.He added, "Our chip business continues to be a key growth engine for the company. With sustained leadership in DDR5 memory interface chips and growing traction for new products, we are well positioned to capitalize on the accelerating demand for high-performance computing and AI infrastructure and drive long-term profitable growth."On June 27, Rambus stock broke out of a cup-with-handle base at a buy point of 63.15, according to IBD MarketSurge charts. It climbed as high as 70.05 on July 21 before retreating.Rambus stock is on the IBD Tech Leaders list.Follow Patrick Seitz on X at @IBD_PSeitz for more stories on consumer technology, software and semiconductor stocks.YOU MAY ALSO LIKE:Apple's Lack Of Clear AI Strategy A Warning Flag, Analyst SaysIntel Stock Tumbles On Surprise Loss, Foundry WoesNvidia, AI Chipmakers Buoyed By Google Capex, Trump PlanFind Winning Stocks With MarketSurge Pattern Recognition & Custom ScreensJoin IBD Live For Stock Ideas Each Morning Before The Open