There is a mod for this now No Godrays Whilst Keeping Volumetric Lights https://www.nexusmods.com/fallout4/mods/26621? Or: You can almost eliminate the performance drain from Godrays, and run them on ultra as well, to avoid the blocks around the edges of things. in the general section of Fallout4Custom.ini Write this: sStartingConsoleCommand=bat godrays (Also set iVolumetricLightingQuality=3, otherwise you do not get ultra quality Godrays) Now create a text file called godrays.txt in the Fallout 4 games root directory and write this in it: gr grid 12 gr scale .8 I will not take credit for this, I did not come up with it, it is listed on the nexus under: Ultra Quality God Rays Performance Fix https://www.nexusmods.com/fallout4/mods/15211 It just does away with Godrays that you do not even see. Ultra Godrays for the same performance hit as low quality ones. I know, you did not ask for the second part, only the first, but this post comes up fourth on google at the moment, when one searches for iVolumetricLightingQuality, and the other 3 do not allow for posts.