Current Terramity versions have a really laggy shader implementation for the Chthonian Void block. This is fixed in the upcoming 1.0 version of the mod, but this small addon will fix the issue in the meantime.
From personal tests, this addon speeds up the rendering speed of Chthonian Void blocks by ~3.5x. This can mean differing changes to FPS depending on how many are rendered and PC specs. Personally, I experienced an increase of ~100 FPS while inside the Chthonic Dungeon structure.
