I assume it does use one for Voxel volumes, but do Surface volumes not go under any such optimization? I ask as I notice the more dense a surface volume is(I work with 10-15 million triangles usually), some operations can be very slow(retopo to 1M can take 8+ hours on draft, accidental double click on the 1 million retopo mesh can take an hour for edges where it seems to selects all edges, sculpt room geometry->close holes various amounts of time...10mins to hour+, delete or fill hole 10 secs+, etc) . Using sculpt brush tools to add details(or live clay with not just push/pull triangles but add/remove) all seem to work pretty fast and responsively.
It's not a hardware issue as far as I can tell, the machines I've used coat on have more than enough grunt. I know quite a few tasks are single threaded, but with an octree or similar perhaps that could use multiple threads by splitting the work across octants? The reason I get the impression octree is not in use is when performing a task like delete or fill hole on a small set of triangles, it would seem the more triangles in the volume, the longer this operation can take, the actual amount of triangles to delete or size of hole doesn't make the difference.
I get the impression these performance issues can be fixed, is it well known as problematic? Or not common for users to work with 10mil + triangles in a surface volume? Is it a size that 3D Coat should be able to handle better?(I edit environmental scan data where voxels isn't really an option).