Recently I started a new char, and because of the type of char, I wanted strong as the companion because what he likes and dislikes are easy to satisfy with that char. Anyways, once I got to a certian level, the elevator ride I had to go through lagged alot, the same with the floor the elevator lead to, and it kept lagging like crazy, so much my computer/fallout 4 crashed very often, and it was overall annoying. My game usually doesn't crash or lag this much. What is causing this/ what can I do to fix this?

EDIT: I tried rush killing the enemies then going back down for the loot to see if that would reduce the lag, and it didn't.

Managed to get farther, and it seems it is the same overall cell in-game that has strong and rex, so it is the top floor.