The Motley Fool analysis suggests that while both Nvidia and AMD are strong players in the booming AI data center infrastructure market, Nvidia is the superior long-term investment. The analysis highlights Nvidia's second-quarter sales more than doubling to $96.2 billion, with Q3 revenue guidance of $108 billion, and its dominant 86% market share in AI data GPU. Despite AMD's data center revenue doubling to $6.7 billion in the most recent quarter and strong CPU market prospects, its trailing P/E ratio of 121 is significantly higher than Nvidia's 29, making Nvidia a cheaper option.