Look i am going to buy a very similar build to this and i have really researched everything about it and i will tell you this i have seen a lot of benchmarks BF4 will work 1080p 60 FPS most of the time MAXED OUT and written maxed out with capital letters because i mean maxed out with AA V-Sync AF HBAO Physx everything even with 150% more resolution scale you will get 60 FPS most of the time and when it's a very intense moment you will get around 30-40 FPS but in real time you won't need V-Sync and wont have to use the 150% scaling and will probably not use full AA so you'll get even more than 60 FPS like all the time if that's the case in this game if you ever run by games that are less than 50 FPS all the time it will be probably something in the game like TombRaider and it's TressFX option or COD:Ghosts and it's bad porting and i have really researched all of this i mean i saw all of it in real-time right in front of me and i never expected a PC for less than 600$ to beat the PS4 specs this fast but there's now and it's this one good luck and have fun buddy.
PS: Sorry for the long comment