Reducing Chunk Lag: A Complete Guide to Pre-Generating Your Minecraft World
When a player explores a fresh area of your server's world, the server must generate all that terrain in real time - calculating biomes, placing ores, populating structures, spawning entities. On a busy server, this is a performance cliff. Multiple players exploring different new areas simultaneously can halve your TPS instantly.
Pre-generation solves this permanently. You generate the terrain once, store it on disk, and every subsequent visit to that area is just a fast disk read.
The Chunky Plugin: The Gold Standard
Install Chunky from SpigotMC. It is the most reliable and performance-conscious pre-generation tool available in 2026.
Basic usage:
/chunky radius 5000
/chunky start
This pre-generates all terrain within 5,000 blocks of world spawn. During generation, server TPS may dip - run this during low-traffic hours or before your server opens.
Progress monitoring:
/chunky status
How Long Does Pre-Generation Take?
Speed varies by hardware. Here are Space-Node benchmark numbers for a 5,000-block radius (vanilla terrain):
| Storage Type | Time to Complete | I/O Bottleneck |
|---|---|---|
| HDD | 45 - 90 minutes | Yes - heavily |
| SATA SSD | 15 - 25 minutes | Moderate |
| NVMe Gen 4 | 5 - 8 minutes | None |
Space-Node uses NVMe Gen 4 storage. A 5,000-block radius pre-generates in under 8 minutes on our hardware. The same task takes over an hour on hosts running HDDs.
Choosing Your Radius
| Server Type | Recommended Radius |
|---|---|
| Small private SMP (10 - 20 players) | 3,000 blocks |
| Public survival server (50 players) | 6,000 blocks |
| Large network hub | 8,000 - 10,000 blocks |
| Skyblock (no terrain) | N/A |
Combine with World Border
Pre-generation only helps if players cannot venture beyond the pre-generated area. Set a matching world border:
/worldborder set 10000
(This sets 10,000 diameter, so 5,000 in each direction from 0,0)
When players hit the border, they cannot generate new chunks. Your pre-generated terrain handles all load from that point forward.
Modded Servers: Special Considerations
Modpacks add biomes and structures from dozens of mods. Pre-generation time scales with mod count - ATM10 terrain generation is significantly slower than vanilla. Run Chunky at server launch, allow 45 - 90 minutes, and schedule it before player sessions begin.
Some mods (like Biomes O' Plenty) must be initialised before you can use Chunky effectively. Always start the server fully, log out, then run the Chunky command from the console.
