Chunk loading theory

I been wondering this for a long time, I cut the maps on my server to 256x256 (0.8.1 world size). My pocketmine.yml has been set up to not load a lot of chunks, but load them faster when needed. Would it be more efficient to load all 256 chunks when the player (players enjoy all chunks loaded) or just load them as they go along?

Preload them. 256 chunks shouldn't spend you much memory.