Fps drops to 15 (in some rooms with light) (Fallout 4)

It was the same in Dragon age inquisition ... everything goes to 60 fps, but it is only worth visiting a light source (like lanterns and just a bunch of light)), it immediately drops sharply to 10-15. Because of what in general it can be? can anyone come across. Previously, I sinned on the Inquisition, but here is the same garbage.