To improve your fps, do the following:
1. The first step would be to increase texture quality by going into Fallout 4s settings and changing the Texture Quality from “Low” to “High”
2. Next you will need to change how many frames per second are being rendered with a simple edit of config file located at %UserProfile%DocumentsMy GamesFallout4Data but it is recommended that you backup this original file in case something goes wrong