Unstable Framerate

I can run 160-200 frames, but the frames look like this (these are not capped): . Even when I cap it to 60 frames they are still jagged and are not stable. How do I stabilize it? It used to be completely fine until I reset my PC and reinstalled windows. Any help would be appreciated, thanks...

Intel 3.2 GHz i5 4570 Motherboard : Intel DH87MC Ram : 8gb corsair vengeance. GTX 650 ti boost 2gb Any CD/DVD Writer around rs 1000. Cooler master cabinet around 3500 1tb HDD WD. Thanks ! And plz any suggestions will be good. I have a budget till rs50000.