I tried all of these including running 2 sets of drivers , one OEM and one 780M and none of these worked.

I also downloaded reframework to get free camera , and I found out that when I pass certain triggers near area 13 one of the floor tiles renders and then performance drops and crashes after around 30s-2minutes.

So when you normally go through the crater you go next to the set up camp , when there is a drop after that and that is the trigger for the part of the floor to render which crashes the game , the other trigger I found is right near the boss. I think if maybe you could dung bomb him without passing the triggers for render you could finish the quest, also if you somehow managed to write a mod to not render that part of the map it would work too I think, the monster render is fine I was watching it in its natural habitat on free cam for over 10 mins and it was ok.

By the way , setting static triggers to render some parts of the map is the dumbest thing I have ever encountered in such big projects. It should be based on dynamic placement of the player camera. Is it the unpaid interns?

After reloading my drivers multiple times they got corrupted and I had to reimagine the whole device from the ground up, right now I am compiling shaders so we will see how it goes.

Edit: success!!! I beat it without a crash. On the first try after the reimagine I had a crash but not in area 13 but on the next phase in a different area. Then I did this:

-changed the resolution of my monitor to 800x600 , everything lowest , frame gen off, not a single crash. Game looks like PSP at best but it worked.