Hunter_Killers :
And xaephod, even though the HD 7970 is the first of the GCN cards, they have not written the driver support for Mantle yet and is all that will be needed for it to start working in games that support it. As to why they didn't do it now since there are more HD7970s in gaming rigs than there are R9 290s I have no idea. Maybe it requires more work of maybe they just want to push the new hardware.Still the benefit will only depend on what CPU you have. If you have a higher end CPU, you wont benefit much.
You really have no idea what you are talking about and obviously never even tried Mantle. 7970's get a colossal benefit even with a powerful CPU behind it.
It would benefit you to post your proof before talking. I am going based on the current previews and considering that the only GPUs currently supported in the 14.1 driver set is the R9 290/290X then we have no way of knowing until the driver supports the other GPUs.
That said, why would a HD7970 benefit more than a R9 290 series when they are the exact same arch just one has more shaders/ROPS?
Again, if you have actual proof, I am more than willing to look but I haven't seen anything but the 290/290X running Mantle currently which was also stated in this article itself as the 7970 and 280 series should be optimized in a future driver release.
Still it is best to wait but I don't see how a API designed to allow better performance from a GPU to benefit a older GPU with lower specs.
And you are right, I haven't tried Mantle because I don't own BF4. Tried the beta and it was ok. No reason to buy a game I will hardly play to try something. I would rather wait and see how it goes then judge.