The default sort works by just taking everything that hasn't been moved already and trying to move it into every slot in turn until it finds the correct spot.

This is absurdly slow, the whole process can be improved by using a faster sort on the items and them moving them into the appropriate slots, based on sorting mode. [First empty, or the next reserved slot in horizontal/vertical modes]

i'm confused, are you not the creator of this mod? are you using this thread as a personal sticky note or something?