zik1zik :
BTW I am upgrading my GPU from a 7770 (which *bleeped* up) So is this a good upgrade from that?
Just look at the BENCHMARK I linked above.
Based on that, an R9-270X should be roughtly 2x faster than an HD7770. That is going to VARY between games, but on average you should see DOUBLE the performance.
MANTLE:
The benefit in BF4 appears to be mainly for those where the CPU power is relatively poor. So YOU should see a bit of a boost, especially in areas that have really LOW frame rates due to CPU bottlenecking in Multiplayer.
It's hard to guess, but I think you might see a 20% boost on average and your LOW frame rates might be a lot higher (i.e. 10FPS to 25FPS). Again, it's an educated guess looking at some benchmarks with different hardware.