Modded Minecraft Server RAM Guide: What You Actually Need

Modded Minecraft servers have unique RAM requirements that differ significantly from vanilla servers. This guide covers modded-specific considerations, optimization strategies, and advanced tuning for modded Minecraft servers.

How Mods Specifically Impact RAM

Understanding how mods consume memory helps you make informed decisions. Unlike vanilla servers where RAM usage is relatively predictable, modded servers vary wildly based on mod selection.

Tech Modpacks: The RAM Hogs

Tech modpacks with extensive automation are particularly RAM-intensive. Every machine, network, and processing system creates entities and data structures that persist in memory.

Why tech mods need more RAM:

• Persistent machine states: Every machine maintains its processing state, inventory, and configuration
• Network systems: Applied Energistics, Refined Storage, and similar mods create complex item/fluid networks
• Tick processing: Automation systems process every tick, creating constant memory churn
• Inventory data: Large storage systems (drawers, storage mods) cache item metadata

If you're running a tech-heavy pack (Create, Mekanism, or All The Mods-style packs), budget an extra 2-4 GB compared to adventure or magic-focused packs of similar mod count.

RAM Requirements by Modpack Type

Different modpack categories have different RAM needs. Use these as starting points, then adjust based on your player count:

Real RAM Numbers for Popular Modpacks

Based on actual server usage with 10-15 concurrent players, here's what popular modpacks typically need:

Modded-Specific Optimization Strategies

Before upgrading RAM, try these modded-specific optimizations that can reduce memory usage by 20-40%:

Performance Mods for Memory Reduction

These mods specifically target memory usage without changing gameplay:

Automation and Entity Management

Tech modpacks create entities that persist in memory. Manage them effectively:

• Limit hopper usage: Use item conduits/pipes instead of hopper chains where possible
• Consolidate storage: Large storage networks (AE2, Refined Storage) are more efficient than many small storage blocks
• Cap automation size: Set limits on farm sizes and machine counts per chunk
• Use chunk loaders sparingly: Only load chunks where automation is essential

World Generation Optimization

Modded world generation can be memory-intensive. Pre-generate your world to avoid generation spikes:

• Chunky (Fabric/Forge) - Pre-generate chunks around spawn before players explore
• Chunk-Pregenerator (Forge) - Alternative pre-generation tool with more options
• Pre-generate at least a 5000x5000 block area (2500 chunks) around spawn
• This prevents memory spikes when players explore new areas

Mod-Specific Settings

Some mods have config options that reduce memory usage:

• Reduce entity spawn rates: Lower mob spawn caps in configs
• Limit chunk loading distance: Reduce view distance and simulation distance
• Disable unused mod features: Some mods let you disable optional features
• Optimize ore generation: Reduce ore vein sizes if the modpack allows

Regular Maintenance

Modded servers benefit from regular maintenance to prevent memory leaks:

• Daily restarts: Clears accumulated memory leaks
• World cleanup: Remove abandoned bases and excessive entities
• Monitor entity counts: Use tools like /forge entity or similar commands to track entity counts
• Archive old chunks: Use plugins/mods to unload chunks that haven't been visited in months

When to Upgrade RAM for Modded Servers

Even after optimization, you may need more RAM. Upgrade if you see:

• Consistent RAM usage above 85-90% even after optimization
• Out of memory errors despite optimization
• Modpack warnings about insufficient RAM
• Frequent crashes during peak player activity
• Adding significantly more players (scale by 1-2 GB per 5 players)

Summary

Modded servers need more RAM than vanilla, and requirements vary by modpack type. Tech-heavy packs need the most, while adventure-focused packs can get away with less. Use performance mods and optimization strategies before upgrading, but don't hesitate to add RAM if you're consistently hitting limits.