The list of most to least demanding was put together after exhaustive research and is available in the Bang for Buck guide.
If you’re having issues with Terrain LOD, it makes me wonder if your CPU or RAM might be struggling with all the polygons. In any event, the list above has been invaluable to many, including myself.
For me, Terrain LOD has been inconsequential while Clouds, Scaling and Terrain Shadows have been the killers… but I’m running an R7 with 32GB RAM. 