How to Host a Cosmic Frontiers Server (Forge 1.20.1 Setup Guide)

Start the server plan at 8 GB RAM, minimum. Cosmic Frontiers runs GregTech underneath its sci-fi/arcane theme, and GregTech's multiblock processing chains and chunk-loaded machines are some of the heaviest tick load in the Forge modding space — 8 GB is the catalog's own recommended floor, not a conservative guess, so don't go below it even for a 1-2 player test.

Import the modpack from a clean source rather than copying a client install. Upload the official Cosmic Frontiers server pack (or let the host's one-click modpack installer pull it) so the mod list, config files, and loader version match what the pack actually ships — a client export regularly drags in client-only rendering mods that have no business running on a dedicated server.

Watch the first boot through to a finished world load before touching anything. GregTech registers a huge number of recipes, materials, and ore-processing chains during startup, so the first boot takes noticeably longer than a vanilla Forge server — let it reach the 'Done' line in the console and confirm no mod threw a crash report before assuming it's ready.

Only invite players once that first clean startup has finished without errors. Letting people join mid-boot, while GregTech is still registering its material and recipe trees, is one of the more common ways a Cosmic Frontiers server corrupts its own world state right out of the gate.

Take a backup before any world import, loader update, or config change. A GregTech multiblock setup — assembly lines, chemical reactors, ore-processing chains — represents hours of progression-gated setup, and a bad update or config tweak that corrupts that machine layout is effectively a full restart for whoever built it.