16k will give 2x improvement in resolution over default textures.
32k - 4x improvement, required 16k to be installed.
64k - 8x improvement, required 16k and 32k.
I downloaded these to see what it looks like but cant see any difference when im on Titan...
Titan-Bump-fake-SE-16k.pak
Titan-Surface-SE-8k.pak
There arent any 'bumps' (mountains/elevation) over there...
I tried to put those files in "addons" folder as well as in "solarsyshd" and no difference.