They did make a specific optimization for A19, though, and it has helped quite a bit when loading an existing world. I cannot for the life of me find the reference now, but it had something to do with the "initializing world" process. Something about culling the # of chunks which must be loaded? Maybe it's a MP thing and changed how much must be downloaded by the client? Anywho, my A19 worlds load up noticeably faster than my A18 worlds of the same size. It's why I wonder what "loading screen" OP is talking about.