Utterly Mad

If it won't there are a ton of mods for degrading the quality of settings and such beyond the default. Greatest tool to start out with would be the configuration tool.
http://www.nexusmods.com/fallout4/mods/102/?
this'll let you do a lot of stuff without having to directly touch the INI files, though some things may require manual modification of them. This lets you set custom resolution and other such things. Give it a try if your comp has trouble with the game.