bBorderless=1
bFull Screen=1
and change to
bBorderless=1
bFull Screen=0
It doubled my fps and removed al stuttering in a I7 4970 and GTX 660.
I LEAVE a Fallout4Prefs, butyou dont have to download it. You can download the .ini and then adjust your graphics in the launcher-settings, but dont touch borderless or full screen.
Thanks to Fluffybumbum.