The Ultimate Guide to Modded Minecraft Performance Optimization | Jangro.com

Whether you're playing BTH - Beyond the Horizons, Prominence II RPG, All The Mods, or any other modpack, poor performance can ruin your experience. This comprehensive guide covers every optimization technique from basic settings to advanced JVM tuning, helping you squeeze every last FPS from your system - even on a potato PC.

Quick Wins: Start Here

Before diving into complex optimizations, these simple changes can dramatically improve performance:

Allocate proper RAM (5GB for 8GB systems, 9-10GB for 16GB+ systems)
Lower render distance to 12-16 chunks
Disable VSync in video settings
Remove unnecessary shaders
Switch to a lightweight launcher like ATLauncher or Prism

If you're still experiencing issues after these basics, continue reading for advanced optimizations.

Choosing the Right Launcher

Your launcher choice significantly impacts performance before you even start the game.

Performance Ranking (Best to Worst)

ATLauncher - Minimal overhead, excellent performance
Prism Launcher - Modern, efficient, great mod management
MultiMC - Lightweight but fewer features
GDLauncher - Good balance of features and performance
Modrinth App - Clean but sometimes doesn't allocate enough RAM
CurseForge - Feature-rich but resource-heavy with Overwolf

What Launcher NOT to Use

TLauncher is a cracked launcher. Don't use this. And if you must, don't talk about it in Discord as it'll get you banned. I'm not here to judge, but if you can, please pay for Minecraft. Not only is it illegal, but it harms developers and is prone to bad performance and breaking.

Migrating to ATLauncher

Download ATLauncher from atlauncher.com.

To transfer your existing world and settings:

Locate your old instance folder
Copy these files/folders to the new instance:
- saves/ folder (your worlds)
- options.txt (settings and keybinds)
- servers.dat (server list)
- xaero/ folder (minimap waypoints)
- schematics/ folder (if using Schematica/Litematica)

Migrating to Prism Launcher

Download Prism Launcher from prismlauncher.org.

Prism makes migration even easier with its import feature:

Method 1: Direct Import (Recommended)

Click "Add Instance" in Prism
Select "Import from zip"
Browse to your CurseForge/other launcher's instance folder
Prism will automatically import the modpack and settings

Method 2: Manual Transfer
Same as ATLauncher - copy these files to your new Prism instance:

saves/ folder (your worlds)
options.txt (settings and keybinds)
servers.dat (server list)
Waypoint/minimap folders (xaero/, journeymap/, etc.)
Config folders if you've customized mod settings

Prism Advantages:

Built-in mod downloader from CurseForge and Modrinth
Easy Java version management
Excellent for mod development
Component-based updates (can update mods independently)
Lightweight with dark mode support

Memory (RAM) Optimization

Optimal RAM Allocation

System RAM	Minecraft Allocation	Notes
8GB	4-5GB	Leave 3GB for system
16GB	8-10GB	9GB is the sweet spot
24GB	10-12GB	Balance performance
32GB+	12-16GB	Only for heavy modpacks

Note: You may have heard that Java performs worse with more than 10GB of RAM. This isn't a fixed limit so much as a practical ceiling - most modpacks simply won't use more than 10GB effectively. Allocating more RAM than needed can actually decrease performance due to longer garbage collection pauses. Some extremely heavy modpacks (300+ mods) may benefit from 12-16GB, but always test what works best for your specific setup.

Setting RAM in Different Launchers

ATLauncher:
Settings → Java/Minecraft → Maximum Memory

CurseForge:
Settings → Game Specific → Minecraft → Java Settings → Allocated Memory

Prism Launcher:
Settings → Java → Maximum memory allocation

Memory Troubleshooting

"Out of Memory" errors: Increase allocation by 1GB increments

Stuttering/freezing: Can be caused by too much OR too little RAM

Too little RAM: Press F3 and watch memory usage in the upper right. If it's consistently in the 90s and frequently hitting 100%, your stutters will correspond to hitting the memory cap. Allocate more RAM.
Too much RAM: If memory usage stays below 60-70% but you still get stutters, try reducing allocation - you may be experiencing long garbage collection pauses.

"Insufficient memory" warnings: Minimum 8GB recommended for most modpacks

JVM Arguments: The Secret Sauce

These optimized JVM arguments work with Java 17+ (required for Minecraft 1.18+):

Standard Optimization (Aikar's Flags)

-XX:+UseG1GC -XX:+ParallelRefProcEnabled 
-XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions 
-XX:+DisableExplicitGC -XX:+AlwaysPreTouch 
-XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 
-XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20 
-XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 
-XX:InitiatingHeapOccupancyPercent=15 
-XX:G1MixedGCLiveThresholdPercent=90 
-XX:G1RSetUpdatingPauseTimePercent=5 
-XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem 
-XX:MaxTenuringThreshold=1

High-Performance Setup (12GB+ RAM)

Add these to the standard flags:

-XX:G1HeapRegionSize=16M -XX:+UseStringDeduplication
-XX:+UseNUMA -XX:+UseFastUnorderedTimeStamps

Using GraalVM for Extra Performance

GraalVM is a high-performance Java runtime that can provide 10-30% better performance:

Download GraalVM from graalvm.org
Extract to a folder like C:\Java\graalvm-21\
In your launcher, set the Java path to the GraalVM directory
Uncheck "Use Java Provided By Minecraft"

Using a Dedicated Server: The Ultimate Performance Boost

One of the most effective ways to improve modded Minecraft performance is to separate the server and client workloads. Running both on the same PC forces your computer to handle world generation, mob AI, chunk loading, AND rendering simultaneously.

Why Dedicated Servers Help

Performance Benefits:

Your PC only handles rendering and client-side mods
Server handles all world simulation, mob AI, and chunk generation
Both can use their full CPU/RAM allocation without competing
Typically 30-50% FPS improvement on the client
No more lag spikes from autosaves or chunk generation

Additional Advantages:

Play from any computer in your house
Friends can join without you hosting
Server runs 24/7 for farms and automation
Easy world backups and management

Option 1: Self-Hosted Second Computer

That old laptop or desktop can be perfect for hosting:

Minimum Requirements for Server:

4GB RAM for light packs (under 150 mods)
6-8GB RAM for medium packs (150-250 mods)
8-12GB RAM for heavy packs (250+ mods)
Any CPU from the last 8 years
50GB+ storage space
Wired ethernet connection preferred

Quick Setup:

Install Java on the server computer
Download your modpack's server files
Run with appropriate RAM allocation
Connect via your local network IP

Option 2: Minecraft Hosting Provider

Professional hosting removes all technical hassles:

Benefits:

No electricity costs or hardware maintenance
Professional DDoS protection and backups
One-click modpack installation
Often better CPU/network than home hosting

Recommended Providers:
See our full comparison: Best Minecraft Hosting Providers

Cost Considerations:

Basic plans start at $5-10/month
Good performance for 2-4 players: $15-20/month
Heavy modpacks with 5+ players: $25-40/month
Compare to: electricity costs, hardware wear, and internet bandwidth of self-hosting

Setting Up for Best Performance

Server Optimization:

Pregenerate spawn area before inviting players
Use the same JVM arguments (without client-specific ones)
Install performance mods like Spark for monitoring
Set view-distance to 8-10 (clients can render further with DH)

Client Optimization:

Can now increase render distance without performance hit
Allocate less RAM (6-8GB instead of 10-12GB)
Disable integrated server settings
Enable "Multiplayer Performance" options in video settings

Local Network Tips

For Self-Hosted Servers:

Use ethernet for both server and client if possible
Set static IP for the server
Port forward if friends need external access
Consider a dedicated server OS like Ubuntu Server or Proxmox

Connection Settings:

Direct connect via local IP (e.g., 192.168.1.100)
Add to server list for quick access
Enable "Use Server Textures" for consistency

World Pregeneration: Eliminate Exploration Lag

Pregenerating chunks is the single most effective way to eliminate lag spikes while exploring.

For Distant Horizons Users (BTH, etc.)

Important: Distant Horizons does its own world generation and chunk saving. DO NOT use Chunky with DH - it's not needed and can actually cause LOD display issues, defeating the whole purpose of having Distant Horizons!

Set LOD Render Distance to 512 chunks
Enable Distant Generation
Set CPU Load to "I paid for the whole CPU"
Leave running for 4-8 hours
Reduce settings after generation completes

Full Distant Horizons guide →

For Standard Modpacks (Chunky)

Note about Lootr: Older versions of Lootr can cause world generation to stall during pregeneration. If you experience stalling, either:

Update Lootr to the latest version, OR
Temporarily disable Lootr in its config during pregeneration, OR
Remove Lootr temporarily and re-add after pregeneration

Install Chunky
Run /chunky radius 5000 (5000 block radius)
Run /chunky start
Wait for completion (2-6 hours)

Server Pregeneration

For servers, run pregeneration during off-hours:

/chunky radius 10000
/chunky start

Monitor with /chunky progress and pause with /chunky pause if needed.

In-Game Video Settings

Critical Performance Settings

High Impact (Change These First):

Render Distance: 12-16 chunks (DH handles distant terrain)
Simulation Distance: 8-10 chunks
Entity Distance: 50-75%
Particles: Decreased or Minimal
Graphics: Fast
VSync: OFF (causes stuttering)

Medium Impact:

Smooth Lighting: Off or Minimum
Biome Blend: 3x3 or OFF
Entity Shadows: OFF
Clouds: OFF

Low Impact (Keep for Quality):

GUI Scale: Personal preference
Brightness: No impact
FOV: No impact

Shader Guidelines

Avoid shaders if struggling with performance
If you must use shaders:
- BSL or Sildur's Enhanced Default (lightweight)
- Disable shadows beyond 80 blocks
- Reduce shadow resolution to 1024
- Turn off volumetric fog/clouds

Storage and System Optimization

Storage Management

Your storage setup significantly impacts Minecraft's performance, especially during chunk loading and world saves.

Why Free Space Matters:

SSDs need 15-20% free space for wear leveling and performance
HDDs fragment more when full, causing slower reads
Minecraft creates temporary files during play
Mods generate cache files that need space

Storage Analysis Tools:

TreeSize Free - Fast, visual directory analysis with export options
WizTree - Blazingly fast NTFS scanner (faster than WinDirStat)
Built-in Windows Storage Sense - Settings → System → Storage (good for quick cleanup)
macOS: Disk Utility or DaisyDisk
Linux: Baobab (GNOME) or Filelight (KDE)

What to Clean:

Old Minecraft instances you no longer play
Backup folders from modpack updates
Screenshot folders (can get huge over time)
Crash reports and logs older than a week
Downloads folder (old modpack zips)
Windows temp files: Run cleanmgr or Disk Cleanup
Browser cache if you download many mods

Power Management Optimization

Windows Power Plans:

Open Control Panel → Hardware and Sound → Power Options
Select "High Performance" or "Ultimate Performance" (if available)
Click "Change plan settings" → "Change advanced power settings"
Adjust these specific settings:
- Processor power management → Maximum: 100%
- PCI Express → Link State Power Management: Off
- USB settings → USB selective suspend: Disabled

Gaming Mode & GPU Settings:

Enable Windows Game Mode: Settings → Gaming → Game Mode: On
NVIDIA users: GeForce Experience → Settings → Enable "Whisper Mode" OFF
AMD users: Radeon Software → Performance → Tuning → Power Tuning: Rage Mode
Disable Xbox Game Bar if not using it (Settings → Gaming → Xbox Game Bar: Off)

Laptop-Specific Tips:

Always plug in while gaming - Battery mode severely limits performance
Elevate laptop for better cooling (even books work)
Consider a cooling pad for extended sessions
Some laptops have a "Performance" key (often Fn + a function key)

GPU Selection (Laptops)

Many laptops default to integrated graphics instead of your dedicated GPU, causing severe performance issues.

Quick Check: Press F3 in-game. If you see "Intel UHD Graphics" or similar under Display, you're using the wrong GPU!

Full Fix: See our complete guide: How to Fix Minecraft Using CPU Instead of GPU

This guide covers:

How to identify which GPU Minecraft is using
Step-by-step Windows Graphics Settings configuration
Finding the correct Java executable for your launcher
Troubleshooting tips

Background Programs & Services

Quick Startup Cleanup:

Press Win + X → Task Manager → Startup tab
Sort by "Startup impact"
Disable HIGH impact items you don't need immediately at boot

Common Resource Hogs to Disable/Close:

Communication Apps: Discord, Slack, Teams (use browser versions or close)
Game Launchers: Steam, Epic, Origin, Battle.net (launch as needed)
Overlays:
- Overwolf (CurseForge companion)
- GeForce Experience Overlay
- Discord Overlay
- MSI Afterburner (unless monitoring)
Cloud Services: OneDrive, Dropbox, Google Drive sync (pause while playing)
RGB/Hardware Software:
- Razer Synapse
- Corsair iCUE
- ASUS Aura Sync
- (Keep one if you need it, disable the rest)
Browser Tabs: Chrome/Firefox with 20+ tabs can use 2-4GB RAM

Pro Tip: Create a batch file to kill unnecessary processes:

@echo off
taskkill /F /IM "Discord.exe"
taskkill /F /IM "Steam.exe"
taskkill /F /IM "OneDrive.exe"
echo Processes terminated. Launch Minecraft!
pause

Entity and Storage Optimization

Reduce Lag from Farms/Automation

Storage Solutions (Best to Worst):

Applied Energistics 2 ME System - Minimal lag, massive storage
Refined Storage - Good performance, user-friendly
Sophisticated Storage - Decent with proper setup
Iron Chests - Okay for small scale
Vanilla chests - Avoid large arrays (causes severe lag)

Farm Optimization:

Limit mob farms to essential production
Use chunk loaders sparingly
Avoid massive Create contraptions near base
Consider alternative mods for automation (less laggy than Create for simple tasks)

Advanced Chunk Loading Strategies

Hyperbox Method (for extreme optimization):

Build farms in Compact Machines/Hyperboxes
Only load when needed
Unload after production
Results in 0 impact when not in use

Smart Chunk Loading:

Use 1x1 chunk loaders at critical points
Activate larger areas only when needed
Use redstone/computer control for scheduling

Driver and System Updates

GPU Drivers

Always use latest stable drivers:

NVIDIA: nvidia.com/drivers
AMD: amd.com/support
Intel: intel.com/content/www/us/en/support

Enable automatic updates in GeForce Experience/AMD Software.

Java Version

Minecraft 1.16.5 and below: Java 8
Minecraft 1.17: Java 16
Minecraft 1.18-1.20.4: Java 17
Minecraft 1.20.5+: Java 21

Always use the latest minor version (e.g., 17.0.11 over 17.0.1).

Modpack-Specific Optimizations

BTH - Beyond the Horizons

Distant Horizons is key: This pack is built around DH - use it for pregeneration, not Chunky
Botania shader bug: If using shaders, disable Botania's shaders in its config to fix Gaia Guardian invisibility
See our full BTH Performance Guide

Heavy Tech Packs (All The Mods, Enigmatica, etc.)

RAM Requirements: Tech-heavy packs often need 10-12GB minimum
Storage Systems: Prioritize getting AE2/RS storage early to reduce chest lag
Chunk Loading: Be selective with chunk loaders - tech automation doesn't always need full-time loading

Large Kitchen Sink Packs (300+ mods)

Disable unused features: Many packs include optional client-side mods you can disable
Particle settings: Reduce particles to "Decreased" - many mods add particle effects
View distance: These packs often require lower render distances (8-12 chunks)

Troubleshooting Common Issues

"Game Freezes Every Few Seconds"

Cause: Garbage collection pauses
Solution:

Reduce RAM allocation (counterintuitively)
Add -XX:+UseG1GC to JVM arguments
Check for memory leaks (F3 shows memory usage)

"Chunks Load Slowly"

Cause: No pregeneration
Solution:

Pregenerate world
Reduce render distance
Upgrade to SSD if using HDD

"FPS Drops Near Base"

Cause: Too many tile entities
Solution:

Replace chest walls with ME/RS storage
Spread out machines
Use fewer item frames/paintings
Disable animations in tech mods

"Server TPS Lag"

Cause: Various
Solutions:

/forge tps to identify laggy dimensions
/forge entity list to check entity counts
Reduce mob farm rates
Limit chunk loaders

Performance Benchmarking

Track your optimization progress:

Before changes: Note FPS (F3), RAM usage, and TPS
After each change: Test in same location
Use Spark mod for detailed profiling
Test scenarios:
- Standing at base
- Flying/running through new chunks
- Near automation/farms
- During combat

Quick Reference: Optimization Checklist

Essential (Do These First)

Allocate 9-10GB RAM (for 16GB+ systems)
Apply JVM arguments
Set render distance to 12-16
Disable VSync
Update GPU drivers

Advanced

Install GraalVM
Full world pregeneration
Custom modpack trimming
Hardware upgrades (SSD, RAM, GPU)

Hardware Upgrade Priority

If you must upgrade hardware:

SSD (if still on HDD) - Massive improvement
RAM to 16GB (if at 8GB) - Allows proper allocation
Dedicated GPU - Even budget cards help significantly
CPU - Last priority for Minecraft

Conclusion

Performance optimization is an iterative process. Start with the quick wins, then work through each section based on your specific issues. Most players see 50-100% FPS improvement after applying these optimizations.

Remember: Every system is different. What works for others might not work for you. Test changes individually and keep what helps.

For modpack-specific help, check their Discord servers or our other guides. Happy mining with your newfound FPS!