Direct answer
Lag while exploring virgin terrain suggests generation; delays when returning to an existing base suggest disk reads, plugin loads or memory pressure. Both can appear as stuttering to players.
How to check it
- Travel through a fully explored, already saved route and record chunk delivery delays.
- Repeat in never-explored terrain with the same player count and view distance.
- Compare spark profiler samples, CPU usage and disk I/O; watch whether generation increases only on the new route.
What to change
- For generation-heavy workloads, pre-generate likely play areas during off-peak hours.
- For slow known-chunk loading, check disk health, storage pressure, plugin chunk tickets and I/O bottlenecks.
- Do not solve every chunk problem by raising worker threads: generation workers and disk I/O are separate.
Software and version notes
Compatibility and safety
Paper exposes separate chunk generation limits, load limits and send limits. The labels refer to different stages, and changing one may not address the bottleneck at another.
Verify the result
Revisit the same test routes and compare delivery time, MSPT, storage latency and server responsiveness.