“The Xbox One graphics API is “Direct3D 11.x” and the Xbox One hardware provides a superset of Direct3D 11.2 functionality. Other graphics APIs such as OpenGL and AMD’s Mantle are not available on Xbox One,” said Microsoft.
So what does AMD have to say for itself? Well, it’s a bit tricky. AMD admits Redmond’s new console does not exactly support Mantle, as the new API is supposed to be exclusive to PCs. However, AMD points out that Mantle creates a PC development environment that’s similar to consoles. It’s not meant to work the other way around.
“By creating a more console-like developer environment, Mantle: improves time to market; reduces development costs; and allows for considerably more efficient rendering, improving performance for gamers,” tweeted AMD. “The console connection is made because next-gen uses Radeon, so much of the programming they’re doing for the consoles are already well-suited to a modern Radeon architecture on the desktop; that continuum is what allows Mantle to exist.”
In other words, AMD insists Mantle is just for PCs, but it argues that it would be pointless on consoles anyway. Mantle is supposed to help PCs cut overhead, which is something console devs don’t need to worry about anyway. The hardware is similar and that's what Mantle is supposed to exploit.