According to Bob Feldstein, the current vice president for technology licensing at Nvidia, the deal between Microsoft and AMD for their custom silicon solution for Xbox One cost the former in excess of a cool $3 billion.
Feldstein, who worked for AMD before moving to Nvidia, revealed the following on his Linkedin profile: "AMD provided a custom silicon solution to Microsoft for the XBox One, a game console and entertainment device. My involvement was focused on business management and supply agreement negotiations."
"This required the coordination of multiple functional teams within AMD, as well as regular customer meetings with leadership teams responsible for handling the chanllenges of complex, muti-year deals. This project is valued at $3+B."
AMD has also worked with Sony and Nintendo to provide similar solutions for the Playstation 4 and Wii U respectively.