Topic on Talk:Final Fantasy XIII
You don't need v-sync and frame limiter. Use only the first if you are really sensible to tearing.. otherwise just RTSS if you want to stabilize framerate.
Anyway... you don't have microstutter because frametime varies a bit. You feel it only when there are massive frame drops. And this could even affect just little fractions of time (overlay refreshes only every second by default, remember)
Since CPU, nor GPU seems to be stressed when game stutters (which is evident during fight) my first theory would be: hdd access lag (that's the most common and simple cause, imo).
Though if you could check the exact framerate timeline (in MSI afterburner nvm, for example) it would be interesting to survey every frame one by one