Ultralight

Name: Ultralight
Price: 8 EUR
Author: Unknown

1.21.6-1.21.11 | Only what you need for performance.

by Unknown

3.6K Downloads

0 Followers

fabricMC 1.21.11lightweightoptimization

Rent Ultralight Server

Screenshots

About this Modpack

ultralightbanner

Performance Comparison

Metric	Vanilla	Ultralight	Improvement
Min Frametime	6 ms	4 ms	~1.5× better
Max Frametime	107 ms	54 ms	~1.98× better
Avg FPS	134	277	~2.07× higher

Tested under simulated gameplay at 16 render distance.

Ultralight is best used on client.

If you're looking to improve your server's performance, try out Lilypad!

Want to play Minecraft with a new little spin? Try Wildflower!

Updating the Modpack & Tags

Before a new Ultralight update gets uploaded, it undergoes simulated gameplay testing to assess performance under normal conditions.
If the update meets our internal performance targets, it will be released with an “A” in the version name.
If it fails to meet those targets, it will be released with an “F” in the version name.

Tags

A — Stable and user-ready; no major issues.
B — Acceptable but below optimal performance targets (FPS and/or frametime slightly off).
F — Performance issues; FPS and/or frametime significantly below target.

OS Compatibility

OS	Compatible
Windows	✅
MacOS (ARM)	✅

Tested on Apple M1. Measurements taken on Windows.

Socials

We have a Discord server!

Available Versions

Ultralight 1.21.11_2.2_Arelease

MC 1.21.11fabric1.4K downloads

March 14, 2026

Ultralight 1.21.10_2.2_Arelease

MC 1.21.10fabric67 downloads

March 14, 2026

Ultralight 1.21.9_2.2_Arelease

MC 1.21.9fabric7 downloads

March 14, 2026

Ultralight 1.21.8_2.2_Arelease

MC 1.21.8fabric41 downloads

March 14, 2026

Ultralight 1.21.11_2.1_Arelease

MC 1.21.11fabric994 downloads

January 20, 2026

How to Set Up a Ultralight Server

Order Server

Choose at least 4 GB RAM (6 GB recommended for Ultralight). Based on player count: per 8 players.

Install Modpack in Dashboard

Open the modpack browser in the dashboard, search for "Ultralight" and click "Install". The fabric loader and Minecraft 1.21.11 are configured automatically.

Start Server & Play

Start the server – all mods are loaded automatically. Share the server IP with friends and play together!

Frequently Asked Questions

Ultralight server crashes or won't start – what to do?

Most common causes: insufficient RAM or wrong fabric loader. Check latest.log for "OutOfMemoryError" → increase RAM to at least 6 GB. For "Mixin" or "ClassNotFoundException" errors: modpack version and loader don't match. With Mado Hosting, loader and Minecraft version are auto-configured on modpack install – preventing most startup issues.

How much RAM does a Ultralight server really need?

Minimum 4 GB, recommended 6 GB for stable performance. per 8 players. Important: Minecraft modpacks need more RAM than vanilla – plan extra per additional player. With Mado Hosting, you can scale RAM up live at any time without data loss (from €8/month).

Can I add custom mods to Ultralight without conflicts?

Yes, but check compatibility: only use mods for the same loader (fabric) and same Minecraft version (1.21.11). Common issues: ID conflicts with recipe mods and incompatible coremod versions. The Mado dashboard mod browser only shows compatible mods and warns about known conflicts.

Ultralight server lagging – performance tips

1) Increase RAM to 6 GB+. 2) Reduce server view-distance to 8 (server.properties). 3) Pre-generate chunks with the "Chunky" plugin. 4) Use /spark profiler to check which mods consume the most tick time. With Mado Hosting, all servers run on NVMe SSDs with dedicated CPU cores – eliminating hardware as a bottleneck.