Direct answer
A world border primarily constrains where players can travel. It does not automatically unload old chunks or eliminate expensive generation inside the permitted area.
How to check it
- Record the border size, player distribution and whether lag occurs near unexplored terrain.
- Use spark profiling during exploration to look for world-generation/chunk costs.
- Check the current border center and radius in the intended dimension before changing it.
- Compare chunk loading and disk behavior with the same player path inside pre-generated terrain.
What to change
- Set a border suited to your map using documented worldborder commands, then separately pre-generate the playable region if needed.
- Do not shrink a border on production until you know where player bases and farms are located.
- Avoid deleting chunks as a casual optimization; data loss requires a separate backup and migration plan.
Software and version notes
The border can indirectly reduce future exploration, but already generated region files remain on disk. Modded dimensions or plugins may apply their own border behavior.
Practical example: Example: shrinking a border from a huge world to a small one may prevent players from exploring new terrain, but the existing hundreds of gigabytes of region files remain. Pre-generation and a controlled world archive plan address different needs; neither is equivalent to deleting active chunks under players.
Verify the result
- Confirm players can reach intended areas and cannot enter newly restricted ones.
- Compare generation-related MSPT before/after with a similar exploration workload.