Since upgrading to 1.14, I am experiencing a few performance issues:

 - When loading a savegame, it takes several seconds before the first blocks become visible; in 1.13, this was only a fraction of a second

• After that, frame rate is choppy, with small pauses at a rate of approx. 1-2 per second; it seems that these pauses are in synch with additional blocks being loaded further in the distance
• Once the initial scene is fully loaded, performance is normal, but anytime new chunks become visible (either because I turn around, or because I start moving), the choppiness comes back
• Loading chunks/blocks seems a lot slower in general than it was in 1.13; I used to see empty chunks in the distance occasionally, and never for longer than about a second or so, but on 1.14, it takes much longer, sometimes 10 seconds or more, and I often end up finding myself inside an "empty" chunk when moving fast (running, riding minecarts, ...).
• Unlike previous versions, I can often see mineshafts, caves, tunnels, etc., from the outside, due to terrain covering them not being loaded yet. It seems that the order in which blocks are being loaded has changed, and this kind of breaks the experience, because I now get to see things I shouldn't be able to see.
• Likewise, I can also routinely see mobs in areas that shouldn't be visible, because it seems that mobs and items are loaded faster / earlier than the blocks surrounding them.

I find all this quite strange, because everything worked near perfectly on 1.13, and now the game is almost unplayable.