How to Host a GregTech New Horizons Server

What Is GregTech: New Horizons?

GregTech: New Horizons (GTNH) is one of the longest and most complex modpacks ever made. Built on Forge for Minecraft 1.7.10, it is a hardcore tech pack where GregTech replaces and reworks nearly every recipe in the game. Progression takes hundreds of hours, moving through the stone age, steam power, low voltage electronics, and eventually into high-voltage industrial systems. The pack includes over 200 mods, all carefully reconfigured so that every material, machine, and recipe feeds into GregTech's progression tree.

GTNH is legendary for its difficulty and its dedicated community. If you want to host a GregTech New Horizons server, expect players who are deeply committed to long-term progression and who will push your server's performance to its limits as they build sprawling industrial complexes.

Server Requirements

Forge and Java Version

GTNH runs on Forge for Minecraft 1.7.10, which requires Java 8. This is non-negotiable. Forge 1.7.10 uses internals that were removed in later Java versions. On Linux, install openjdk-8-jre-headless. On a managed panel, select Java 8 from the version selector. The GTNH team distributes a server pack with the exact Forge build, always use it.

RAM Allocation

Player Count	Minimum RAM	Recommended RAM
1–5 players	6 GB	8 GB
6–10 players	8 GB	10 GB
10–15 players	10 GB	12 GB

GTNH loads over 200 mods with tens of thousands of custom recipes. The recipe graph alone consumes significant memory. Avoid allocating more than 12 GB on Java 8, the old garbage collector struggles with heaps above that threshold and causes long pause spikes. Use the RAM calculator as a starting point when you plan to host a GregTech New Horizons server.

Downloading and Installing

Download the GTNH server pack from the official CurseForge page or the GTNH GitHub releases. Extract into your server directory and start:

java -Xms6G -Xmx8G -jar forge-1.7.10-*.jar nogui

Accept the EULA and restart. The first boot is slow (5 to 10 minutes) as 200+ mods load and GregTech generates its massive recipe graph. Subsequent boots take 3 to 5 minutes.

Config Tweaks

Recipe Caching

GregTech calculates recipes on startup. If you notice the server is slow to process crafting requests, ensure recipe caching is enabled in GregTech's config. The GTNH pack usually ships with this enabled, but verify after updates.

Pollution System

GTNH includes a pollution mechanic where machines generate pollution that affects the environment. The pollution system ticks per chunk and can be a performance consideration on servers with many players building large factories in different regions. Adjust pollution spread rate in the GregTech config if TPS suffers.

Common Issues

Java Version Crashes

Running Java 17 or 21 with Forge 1.7.10 crashes immediately with reflection errors. This is the most common mistake new admins make. Always use Java 8.

Recipe Conflicts

With 200+ mods and custom recipes, occasional recipe conflicts appear after pack updates. The GTNH team resolves these quickly, so keep the pack updated to the latest stable version. Check the GTNH Discord for known issues before reporting.

Chunk Loading and Machines

GregTech machines must remain in loaded chunks to operate. Players use chunk loaders extensively. On a 10-player server, chunk loaders can keep hundreds of extra chunks active, dramatically increasing tick costs. Set a per-player chunk loading limit through the chunk loader mod's config.

Performance Tuning

Set view-distance=8 in server.properties (1.7.10 does not have simulation-distance). Reducing view distance is one of the few effective levers on this version.

JVM flags for Java 8:

java -Xms6G -Xmx8G -XX:+UseG1GC -XX:MaxGCPauseMillis=100
-XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=30
-XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M
-XX:G1ReservePercent=20 -XX:InitiatingHeapOccupancyPercent=15
-jar forge-1.7.10-*.jar nogui

Java 8 G1 tuning is different from modern JVMs. Our JVM flags guide covers the specifics. For another 1.12.2 era pack, see our RLCraft guide. If you want a modern kitchen-sink experience instead, the ATM10 guide shows the other end of the spectrum.

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