If you drop a lot of things, it can take quite some turns. Besides that I didn’t found any documentation how the time is computed (by volume/item count/weight?), I had multiple characters (almost) die because I dropped a lot of loot at the same time, jsut now giving a zombear 30 turns time to come into view and kill me while I dropped 2 books, 5 gallons bleach and some other things.
Dragging things around (as in put things in advanced inventory from x->y, none of it the inventory) doesn’t cost any time, though, which I think isn’t really overpowered (what can you accomplish with it), but it is a huge contrast.