How to Properly Pre-generate a World? (Chunky)
Terrain generation is the most CPU-intensive process on a Minecraft server. When a player runs into unexplored regions, a single server thread must perform billions of complex calculations in real time: generate a 3D noise grid, determine biomes, place caves, inject ores, and generate structures. If 5 players do this simultaneously in different directions, the server chokes and immediately drops TPS.