How do I pre-generate the world with Chunky to reduce lag? — Minecraft

Q: What radius should I use?

5000 is a reasonable starting point for many servers. Choose a radius that matches how far you expect players to roam — a larger radius takes longer to generate.

Q: Can I pause it if it's slowing the server?

Yes, run chunky pause in the console to stop temporarily, then resume when convenient.

Generating chunks on the fly — which happens whenever players explore new terrain — is one of the biggest sources of server lag. Pre-generating your world ahead of time trades a one-time CPU burst now for smooth exploration later.

Why pre-generation helps

Every time a player walks into ungenerated terrain, the server has to build those chunks in real time, which spikes CPU and causes stutter. If you generate the terrain in advance, players move through already-built chunks and the server has far less work to do while they explore.

How to pre-generate with Chunky

Install Chunky from the Plugins tab (a Fabric/Forge version also exists for modded servers) and restart.
In the Console, run chunky radius 5000 to set how far out to generate, then chunky start to begin.
Let it finish, watching the progress in the console. You can pause at any time with chunky pause.

Tip: Do your pre-generation before opening the server to players. The generation itself is CPU-heavy, so it's best done while nobody's on.

Frequently asked questions

Does Chunky work on modded servers? Yes — a Fabric/Forge version of Chunky exists, so you can pre-generate on modded setups too. Install it from the appropriate tab for your software.

What radius should I use? 5000 is a reasonable starting point for many servers. Choose a radius that matches how far you expect players to roam — a larger radius takes longer to generate.

Can I pause it if it's slowing the server? Yes, run chunky pause in the console to stop temporarily, then resume when convenient.