How to Host a Fabulously Optimized Server

Start the server plan at 4 GB of RAM. Fabulously Optimized adds zero content — no new items, mobs, or dimensions — so despite being listed with a higher RAM figure in some catalogs, a 4 GB floor is what the pack actually needs once it's live; it's just a leaner vanilla-plus experience than a content modpack of the same mod count.

Import the modpack through a clean install flow rather than copying mods out of your own client install. Fabulously Optimized ships as a Fabric modpack with a specific mod-loader version and Sodium/Lithium/Iris-family performance mods pinned together — a mismatched manual copy is the most common way to break shaders or crash on launch.

Watch the server log through the full first boot. Because this is a performance-and-visuals pack, confirm the rendering and optimization mods (Sodium, Lithium, and the shader/distant-horizons layer if included) initialize without a mod-loader version mismatch before you consider the server ready — these are the mods most sensitive to a wrong Fabric version.

Only invite players after that first boot completes cleanly and the world has fully generated the spawn area. Since there's no new content to test, your main pre-flight check is purely technical: did everything load, and is the tick rate stable.

Take a backup before importing an existing world, updating the Fabric loader, or changing any performance mod's config. A world import gone wrong on a vanilla-plus pack still costs you the same thing it would on any pack — your players' actual world — so protect it before any change that touches the modpack version.