I went to bed last night with no issues with Fallout 4, I woke up today with a stuttering/trailing low framerate on my 50" 4K 60hz TV. I've tried a few things so far.
1. Made sure Fallout4prefs.ini had iPresetInterval=0. It was at 1, but changing it to 0 made the fps skyrocket to the hundreds, but the stutter was still there.
2. Limited fps to 60, but the stutter was still there.
3. Disabled VSync with no improvement.
4. Enabled VSync with no improvement.
5. Scoured Google looking for assistance, but didn't see anything other than what I had already tried.
6. Tried playing other games to be sure it was an issue confined to Fallout 4, it was.
I'm out of ideas, I just want the game to go back to the way it was before, liquid smooth 60 fps @ 1080P.