Modded Minecraft server: how much RAM per modpack

How much RAM does a modded Minecraft server need? The short answer

A modded Minecraft server needs 3 to 4 GB for a light pack of 20 to 60 mods, 6 to 8 GB for 80 to 150 mods on Forge or NeoForge, and 10 to 12 GB for a big pack of 250+ mods. Once you pass 10 players, move up a tier. Treat these figures as rules of thumb and check them against your modpack's own page.

In short

• Light Fabric pack: 3 to 4 GB. Mid-sized Forge/NeoForge pack: 6 to 8 GB. Kitchen sink: 10 to 12 GB or more.
• Too much RAM can lengthen Java's garbage collection pauses, so keep a 1 to 2 GB margin and no more.
• Game logic runs on a single main thread, so CPU clock speed matters as much as RAM.
• CurseForge modpacks install in one click from FlyPanel, with no command line.
• Three worked examples help you pick a plan and avoid overpaying.

Pack type	Typical loader	2-5 players	10 players	20 players
Light (20-60 mods)	Fabric	3 GB	4 GB	5-6 GB
Mid-sized (80-150 mods)	Forge / NeoForge	6 GB	8 GB	10 GB
Kitchen sink (250+ mods)	NeoForge / Forge	8-10 GB	10-12 GB	12-16 GB

Start with your modpack's CurseForge page, which often lists a recommended server RAM. The pack author has tested it and we haven't, so their figure wins. Our table fills the gap when that guidance is missing or when your group outgrows what the author planned for.

What really drives RAM usage up

The number of mods matters less than what they do. These weigh the most:

• world generation mods and extra dimensions;
• tech and automation (Create, Mekanism), whose machines run around the clock;
• view distance and simulation distance;
• chunk loaders, which keep areas active even with nobody nearby;
• an unexplored, non-pregenerated map, where every new area is generated on the fly.

Take ten players. Spread across ten different areas, they load far more chunks than if they all share one base. If your group likes to explore, take the next tier up.

Too much RAM is a problem too

Java frees unused memory through its garbage collector. When the allocation is oversized (24 GB for a pack that uses 6), clean-ups become rarer but longer. You feel it as micro-freezes, even on a powerful machine.

So keep 1 to 2 GB of headroom above your measured need. To measure it, install the spark profiler (available on Modrinth and CurseForge). It shows the memory actually in use, plus TPS. For more on the subject, see how view distance affects RAM and TPS.

Forge, NeoForge or Fabric: which is lightest on the server side?

Fabric is the lightest: it starts quickly and its mods are often smaller. But most big modpacks run on Forge or NeoForge, and you rarely get to choose anyway, because the pack dictates the loader.

NeoForge is a fork of Forge, officially announced on 12 July 2023 by the team behind it. You see it more and more on recent Minecraft versions, while Forge remains common on older ones (1.12, 1.16, 1.20.1).

Server-side optimisation mods exist: Lithium, FerriteCore, ModernFix, C2ME. Their availability varies by loader and Minecraft version, so check each one's page. Many modpacks already bundle them. Don't add any without testing with spark.

One mix-up comes up constantly: Paper, Purpur and Spigot run plugins, not mods. As for "hybrid" servers that promise both, steer clear, because they undermine stability. For a vanilla or plugin-based project, read our page on how much RAM a Minecraft server needs.

Why single-core CPU speed matters as much as RAM

The server runs its main loop (entities, machines, redstone, mobs) on a single thread. The game aims for a fixed number of ticks per second. As soon as the CPU takes longer to compute each tick, TPS drops.

A processor with lots of cores but a low clock speed will therefore give you poor TPS, even with 16 GB of RAM. The symptoms are easy to spot: machines slowing down, blocks reappearing, actions replayed late.

At Fly-Serv, servers run on Ryzen 9 7950X3D processors. AMD quotes up to 5.7 GHz at boost, and the chip carries 128 MB of L3 cache, including 3D V-Cache. On a big pack that cache makes a difference: the server makes a huge number of memory accesses, and more of the data stays close to the core. DDR5 ECC memory and NVMe Gen4 drives, meanwhile, speed up chunk generation and loading.

In practice, your TPS holds up better when everyone fires up their factories at once. To balance RAM and CPU together, read our piece on what really makes a game server perform.

Which plan should you choose for your modpack and group?

Fly-Serv's Minecraft plans start at €2.99/month. Exact RAM tiers and prices are on the Minecraft Server Hosting page. Three typical cases to reason from:

1. Light Fabric pack, 3 to 4 friends: aim for 3 to 4 GB. One of the entry-level plans is enough, so don't pay for more.
2. Mid-sized NeoForge pack, 5 to 8 players: aim for 6 to 8 GB. This is the most common case, and a 1 GB margin saves you from nasty surprises here.
3. Big kitchen sink modpack, 10 players: aim for 10 to 12 GB, pregenerate the map and limit chunk loaders. If the pack's page recommends more, follow it.

There's no commitment: if the pack grows or the group gets bigger, you switch plan. Take a backup before you do.

On budget, you get 5% off for 3 months, 10% off for 6 months and 20% off for 12 months. Wait until your pack is validated before committing for long. For modded play we also recommend the Backup option (+€1.99/month), because a pack update can corrupt a world. Anti-DDoS protection is included, which will matter the day the server goes public.

Installing a CurseForge modpack without the command line

Yes, you can: FlyPanel installs CurseForge modpacks in one click, without you touching Java or the pack's server files. The steps:

1. Choose your plan. The server is delivered in under 60 seconds.
2. In the panel, select the modpack and its version.
3. Start the server.
4. Follow the live console and logs until the "finished loading" message appears.

Three points need attention. Use the same pack version on the client and the server, or the connection will fail. Check the Java version your Minecraft version requires too: recent versions need a newer Java than older ones. Finally, take a backup before every update.

Prefer full control as an admin? The Pterodactyl VPS is the alternative.

Frequently asked questions

How much RAM does a modded Minecraft server need?

Allow 3 to 4 GB for a light pack, 6 to 8 GB for 80 to 150 mods and 10 to 12 GB for more than 250 mods. Add a tier beyond 10 players. Look at the recommended RAM on the pack's CurseForge page first.

Is 8 GB of RAM enough for a big modpack like All The Mods?

8 GB will often get you started and playing with two or three people, but it's tight for a group. With around ten players on a pack that size, aim for 10 to 12 GB, then measure with spark.

Forge, NeoForge or Fabric: which uses the fewest resources on a server?

Fabric is generally the lightest. But the loader depends on the modpack: a NeoForge pack won't run on Fabric. So pick the pack you want to play first.

Why does my modded server lag when it has plenty of RAM?

Most often the main thread is saturated: a CPU that's slow on a single core, too many chunk loaders or too many active machines. Oversized RAM can also cause garbage collection pauses. Run a spark profile to find the cause.

Can you install a CurseForge modpack on a server without the command line?

Yes. With FlyPanel, you select the modpack and its version, then start the server: installation takes one click. You then follow the start-up in the console.

Can you change plan if the modpack gets too heavy?

Yes. There's no commitment, and you can move up a plan if the pack or the group grows. As a precaution, take a backup before the change.

Your next step: measure, then rent

Note the recommended RAM on your pack's CurseForge page, then find your row in the table. Next, pick the matching plan on the Minecraft Server Hosting page and install your modpack in one click. Add the Backup option (+€1.99/month) to protect your modded world during updates.