I would believe it would.
"The design goals of Mantle are to allow games and applications to utilize the CPU and GPU more efficiently, eliminate CPU bottlenecks by reducing API validation overhead and allowing more effective scaling on multiple cores, provide faster draw routines, and allow greater control over the graphics pipeline by eliminating certain aspects of hardware abstraction inherent to the current prevailing graphics APIs"
But this API is pretty much new, and only a few game dev's are using it, so it'll take a while for AMD to do something big, and others to use it. So it'll take a while for mantle to get its self up.