Hi I'm playing Fallout 4 about 5 hours..Everything was fine on High setting on my PC..But since i go to Diamond City and doing Nick Valentine quest..The game is suttering crazy..The heaviest drop FPs place is in Boston Common..Drop from 40 to 2 FPS and suttering every 2 second .i'm finding tweak,ini,fix but didn't working...

My dxdiag file: