Minecraft wiki entry for Spawn_chunk, associated text: Normally, old chunks beyond player's chunk loading distance get unloaded from the memory and new chunks get loaded into the memory. Because of this, events such as redstone mechanisms and farms in unloaded chunks stop processing. Since spawn chunks remain loaded, events occurring in them continue to process, even if no players are nearby. If the world spawn is set to a laggy area using commands, such as an area with many redstone clocks, lag is present wherever the player is in the world.