I did a few LOD tests at Innsbruck to highlight the visual differences and performance hit for each LOD step. You can see in this example, the visual difference between the default 2 and 4 is significant. The rendering distance of the trees and terrains is significantly increased on the mountain directly down the centerline. The difference between 4 and 6 is less noticeable on the mountain directly in front, but the more distant peaks and the relief directly to the right of the runway is better defined with more sharpness. At LOD at 9, the difference is barely noticeable, as any changes are probably well outside the viewing area. The difference at LOD at 9 is probably noticeable at altitude, but I’d argue the viewing distance is so far, you probably won’t even notice those additional trees or terrain rendering.
For the performance hit, I’d say about 3-4 fps hit per LOD step of 2. Surprisingly the VRAM usage doesn’t increase significantly until about LOD = 6. System memory increased for each step, but not really significantly until LOD = 6. I still maintain that for my system, the sweet spot is at LOD = 4 or 6 (I prefer 6). Others may have problems running beyond LOD = 2, but this type of setting is entirely personal preference of performance vs visual quality.
It should be worth noting that LOD is a radius defined around your aircraft - so a circle in simple terms. If you just assume the area of a circle (πr^2), each step of LOD (the radius) increases the area rendered in the circle exponentially by a factor of 2.
System specs: Ryzen 5950X, Asus TUF 3090, 64 GB 3600. Resolution set to 3840x1600, render scaling at 120%. Ultra preset (customized) with texture supersampling at 8x8, and both shadow sizes set to 2048.
LOD = 2:
LOD = 4:
LOD = 6:
LOD = 9:
