ATM9 at a glance
| Minecraft version | 1.20.1 |
|---|---|
| Mod loader | Forge |
| Java | Java 17 (the 1.20.1 requirement, see Change the Java version) |
| Scope | around 400 mods, kitchen sink without a fixed quest path |
| Source | CurseForge - installable with a click in the panel |
| Goal | the ATM Star as the endgame recipe |
| Variants | ATM9 (standard) and ATM9: To the Sky as a skyblock offshoot |
| Recommended plan | plan L for small groups, plan XL from around five players |
Published on
ATM9 server hosting
Prepaid from €2.99 / month, unlimited slots, no minimum term. The right plan is listed in the RAM table below.
Plans & pricesWhy ATM9 keeps running alongside ATM10
With All the Mods 10, a successor has long existed - yet many groups still deliberately start on ATM9. The reason is mod maturity: 1.20.1 is the best-supported modern Minecraft version; practically every major mod has been fully ported to it and tested for years. Applied Energistics 2, Mekanism, Create, Ars Nouveau, Occultism and the dimensions from Twilight Forest to Deeper and Darker mesh cleanly here.
ATM10, on the other hand, relies on 1.21.1 and NeoForge, where individual mods are still missing or exist in more recent ports. For a run that is supposed to last for months, ATM9 therefore remains the conservative choice - especially if you bring an existing save or want to add add-on mods that do not exist for 1.21 yet.
Kitchen sink means: the pack does not give you a direction. There are quests as a reference, but no compulsion. That is exactly what makes ATM9 the typical friends' server pack - everyone builds what they like in their own corner, and the base grows over months.
What ATM9 actually uses on the server
ATM9 loads a server in two separate ways, and confusing them is the most common planning mistake:
- RAM scales with the number of loaded chunks and dimensions. Every player in a dimension of their own - Mining Dimension, The Other, Twilight Forest - keeps additional chunks in memory. Four players in four places cost much more than four players in one base.
- Tick time scales with running automation. A fully built ME network, Mekanism factory chains and dozens of mob farms cost CPU time per tick - regardless of whether anyone is online. This is why TPS drop on long-running servers even when RAM is still free.
On top of that comes the FTB Chunks effect: claimed and force-loaded chunks stay active after logging out. That is intended - the factory is supposed to keep running - but it raises the base load permanently. If TPS drop, first look at the number of force-loaded chunks, not at memory. How to measure this is described in Lag and TPS.
Storage and world growth
ATM9 brings around a dozen additional dimensions. Each of them creates its own region files the first time it is entered, and the Mining Dimension is typically mined out over large areas. A world that runs for half a year with four to six players usually ends up in the mid single-digit to low double-digit gigabyte range.
Plan L comes with 60 GB of NVMe, plan XL with 120 GB - both are enough for ATM9 with headroom for your own backups. Important: backups are self-service with us. You create them via the backup area in the web interface or download the world via SFTP; it does not happen automatically. A backup is mandatory before every pack update, because a mod jump can irretrievably remove blocks and items. The process is described in Create backups.
Which plan for ATM9?
The thresholds below apply to this pack - a light Vanilla+ pack and a kitchen-sink pack with a hundred running machines behave completely differently. You can upgrade at any time without losing data and only pay the difference.
| Group | Plan | RAM | Price | Why | Order |
|---|---|---|---|---|---|
| 1-3 players, early | Plan L | 8 GB | €11.99 / month | Plan L is easily enough to start - there is hardly any running automation in the first hours of play. | Order L |
| 4-6 players | Plan XL | 16 GB | €21.99 / month | As soon as several ME networks and factories run permanently, the 16 GB tier is the safe choice. | Order XL |
| Late game, many farms | Plan XL | 16 GB | €21.99 / month | Large multiblocks, dimension travel and force-loaded chunks eat memory regardless of the number of players. | Order XL |
| Just to try it out | Plan M | 4 GB | €5.99 / month | Starts up, but without headroom. Not recommended for a serious run. | Order M |
The memory is taken proportionally from the plan via -XX:MaxRAMPercentage - you don't need to maintain a fixed -Xmx. The basics are covered in the RAM guide.
Setting up ATM9 on the server
- Stop the server in the web interface - setup and version changes only take effect with the server stopped.
- In the guided setup, choose Forge and search for ATM9 via the CurseForge installer. The panel sets loader version and dependencies automatically.
- Under Startup, check in the Docker Image field that Java 17 is active. Java 21 does not run reliably with 1.20.1 Forge.
- Start the server. The first start takes several minutes because Forge pulls its libraries and registers all mods once - that is normal, do not abort.
- Wait in the console for the line
Done, then connect via IP and port. The client needs the same ATM9 version as the server. - Add a daily restart in the restart scheduler - with packs of this size, that keeps TPS noticeably more stable.
Common pitfalls with ATM9
Server no longer starts after the update
Cause: ATM9 updates regularly swap individual mods. If an old mod file stays in the mods/ folder, it collides with the new version.
Fix: Back up before the update, then check the mods/ folder against the file list of the new pack version and remove leftovers via SFTP. Details in Server does not start.
TPS drop although RAM is free
Cause: Too many force-loaded chunks via FTB Chunks, plus mob and item farms that keep running offline.
Fix: Go through the players' claims and remove force-loads that are no longer needed. A tick report shows which dimension uses up the time.
Players get kicked when changing dimensions
Cause: The server generates many chunks at once the first time a new dimension is entered; the client runs into a timeout.
Fix: Do not let several players enter a new dimension for the first time at once. After the first pass, the effect no longer occurs.
Items have disappeared after a mod update
Cause: If a mod was removed from the pack, Forge deletes its blocks and items when loading the world.
Fix: Only update with a prior backup. If it has happened, only restoring the backup helps - see Create backups.