Will upgrading a cpu improve performance or fps? (For gaming use)?

Will upgrading my cpu improve my performance or fps? What I have…

Asus a55m-s motherboard
500w power supply
Nvidia geforce 660
AMD a6 5400

If it helps… I mostly play Black ops 3, Dark souls 2, Minecraft, Mortal kombat x,Eveonline, Team fortress 2, Games like that.

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