Nvidia has agreed to buy assets from Groq, a designer of high-performance artificial intelligence accelerator chips, for $20 billion in cash, according to Alex Davis, CEO of Disruptive, which led the startup’s latest financing round in September. Davis, whose firm has invested more than half a billion dollars in Groq since the company was founded in 2016, said the deal came together quickly. Groq raised $750 million at a valuation of about $6.9 billion three months ago. Investors in the round included Blackrock and Neuberger Berman, as well as Samsung, Cisco , Altimeter and 1789 Capital, where Donald Trump Jr....