Helium

Name: Helium
Price: 12 EUR
Author: Rezombium

We're happy to finally introduce support for 1.21.5 with Helium version 1.0.0. Happy crafting!

by Rezombium

85 Downloads

0 Followers

fabricMC 1.21.5lightweightoptimizationtechnology

Rent Helium Server

Screenshots

About this Modpack

Helium Windows trys to provide a modpack of the best optimization mods available, make for maximum performance. Thanks to Rezombium/me, it often is better than other optimization modpacks in benchmarks, and when it doesn't, I see why to make it better. Helium is with maintainability and quality in mind. We also added mods for quality while still aims for perfect frames as a 32, 32, 32 renders it runs solid 600+. Also with 15, 15, 15 renders it can run 900+.
(If that causes issues, feel free to ask for support in our Discord server and we'll try to help out! Also join if you have any feedback you want to share - all is welcome.)

Available Versions

Exium Windows 1.0.0release

MC 1.21.5fabric85 downloads

June 13, 2025

How to Set Up a Helium Server

Order Server

Choose at least 6 GB RAM (8 GB recommended for Helium). Based on player count: per 5 players.

Install Modpack in Dashboard

Open the modpack browser in the dashboard, search for "Helium" and click "Install". The fabric loader and Minecraft 1.21.5 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

Helium 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 8 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 Helium server really need?

Minimum 6 GB, recommended 8 GB for stable performance. per 5 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 €12/month).

Can I add custom mods to Helium without conflicts?

Yes, but check compatibility: only use mods for the same loader (fabric) and same Minecraft version (1.21.5). 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.

Helium server lagging – performance tips

1) Increase RAM to 8 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.