Bf4 PC...... 30 or 60hz why?

why is the frame rate reduced to 30 or 60 hz...now it stutters and chugs like a u know what!!!

when a while back I was getn like 120+ fps nice and smooth with a.... 970gtx most settings maxed, i7,+etc

ANd I paid a lot of money to play at THIS RATE,,, Now my score RATE's gone DOWN etc... because of above's comment.