Or it could be the blank textures. Skyrim had a few, and you could recover a lot of FPS by deleting them, or finding a mod that deletes them for you. Fallout 4 was egregious with blank textures. It was about the only thing that gave me FPS problems until I got a mod that deleted them. I have no idea the point of applying a texture that is completely blank, especially when they don't actually do anything in game. The FPS hit comes from the game rendering the blank textures. I know that doesn't make sense, but imagine you have a sheet of perfectly transparent material and you wrap it around something. The material reflects no light, all light passes through it. It changes that light in no way. It also doesn't alter the appearance of the object in any way, and yet keeping it attached to that object means extra tape (power usage). That's the kind of thing I'm talking about. Delete those blank textures and you'll get a decent FPS boost and no change in the grayfix. When I got my PC back in 2011, I got it specifically so I could play skyrim. It was advertized as a PC that was made for games of the day. I still went through and got rid of blank textures and gained a good 5-10 FPS.
I can host 7 days, but I can't promise the FPS will be stable. I host for a friend in italy though, and she seems to have no problem with it.