Did anyone care to read the Highlights & Details section.. There is NO CPU support yet only some APUs & some GPUs, even the Radeon guy on Twitter has said Mantle will not work correctly with any of the FX series "Yet"

I guess it's just more and more waiting to give the API a real benchy blast.
Edit:
Mantle Beta driver
AMD's Mantle is a groundbreaking graphics API that promises to transform the world of game development to help bring better, faster games to the PC
Performance gain of up to 45%(versus the DirectX version) for Battlefield 4 on the R9 290 Series
Performance gain of up to 200% (versus the DirectX version) for Star Swarm on the R9 290 Series
AMD Catalyst 14.1 Beta must be used in conjunction with versions of these applications that support Mantle
It is expected that these applications will have future updates to support additional AMD Mantle features
AMD Mantle Beta driver is currently supported on:
AMD Radeon™ R9 Series GPUs
AMD Radeon™ R7 Series GPUs
AMD Radeon™ HD 7000 Series GPUs
AMD Radeon™ HD 8000 Series GPUs
AMD A10-7000 Series and AMD A8-7000 Series APUs
For additional details please see the AMD Mantle Technology FAQ on amd.com