Like I said, your CPU is bottle necking that video card. Since, you are already at 4.4 GHz and I believe can not overclock any more, there is only one way to get things sorted out - upgrade the CPU, you'd notice a rise in frame rates by 5-15 fps (under same settings and conditions) if you upgrade to an entry level cpu like the i3 6100.
And yes if you are wondering, why you can run Hitman Absolution but not BF4, then you should know that how your system can run a certain game is also dependent upon the engine being employed by the title and how the game has been optimised to run upon a particular platform.
I am pretty sure you'd be able to play plenty of other titles with that set up but would be left severely wanting for some more power while trying to run some other (like BF4). So, whether to upgrade or not, is entirely up to you and the types of games you'd want to play.