I have noticed a dramatic drop in FPS (60-80 down to 10-15) when I'm close enough to bedrock to start seeing void fog effects, with the slowdown increasing with further depth. Playing around with other settings, it appears to be just the particle effects which are causing the problem - setting particles to "Minimal" or "Disabled" runs as fast as being on the surface.

Would it be possible to add a setting to adjust only the void particle density, independent of the global particle density setting? I'd still like to be able to see particles in other circumstances (when there's not a landscape full of bedrock and void particles nearby), and I'd rather not have to go into my video settings to enable/disable particles every time I leave/approach bedrock - an issue I suspect will get worse once I get further into VoidCraft.