You will not be able to play BF4 on ultra with this set-up. For ultra you will at least need a FX-8320 or a i5 4670K and a GTX 770 or a Radeon HD 7970. With that set-up you should be able to run BF4 at medium settings at 720P.
With just a 650 SC you should be OK but if you ever want to upgrade your GPU I suggest you also upgrade your motherboard and CPU to something in the FX series (FX-6300 or better).
You will not be able to play BF4 on ultra with this set-up. For ultra you will at least need a FX-8320 or a i5 4670K and a GTX 770 or a Radeon HD 7970. With that set-up you should be able to run BF4 at medium settings at 720P.