How to Allocate More RAM to Minecraft

Minecraft ships with just 2 GB of RAM allocated by default, which is fine for a fresh vanilla world but runs out the moment you load mods, join a busy multiplayer world, or build something ambitious. Crashes, ‘Out of Memory’ errors, missing chunks and severe stutter are almost always memory-starvation symptoms rather than a broken game. This guide explains how to allocate more RAM to Minecraft on every side of the setup: the default Java launcher, third-party launchers, a self-hosted machine, and a GPORTAL Minecraft server, without wasting memory on a config that does not need it.

What Is RAM in Minecraft (and When Do You Need More)?

RAM (Random Access Memory) is the short-term working memory your computer uses to hold everything currently in play: open programs, the operating system, and the entire active state of your Minecraft world. Every chunk you load, every mob the server tracks, every block-entity tile and every mod that initialises on startup occupies a slice of RAM. When the allocation runs out, Java can’t free memory fast enough and the game stutters, freezes or crashes outright.

Minecraft is especially memory-hungry because it loads world chunks dynamically as you move, stores entity data for every nearby mob, and stacks additional assets for every mod on top of that. More mods, more entities and higher render distance means more RAM is needed. 

How Much Minecraft RAM Do I Need?

Use this as a rough reference. For full breakdowns by player count, modpack size and performance tuning, see the dedicated articles on vanilla server RAM and modded server RAM:

• vanilla client: 4 GB covers most modern setups, 6 GB for big render distance or heavy redstone
• modded client: 6-8 GB for medium packs; 8-10 GB for kitchen-sink packs like All the Mods 10, rarely more than 12 GB
• vanilla server: 2 GB for up to 5 players, 4 GB for 5-10, 6 GB+ for larger groups
• modded server: 4 GB minimum, 6-8 GB for most mid-size packs, 10 GB+ for heavy modpacks

The two universal rules: never give Minecraft more than half your system’s total RAM, and never push the client past 12 GB. Beyond that, Java’s garbage collection pauses start hurting performance instead of helping.

Before You Change the Minecraft RAM Allocation

You should do two quick checks before editing anything. They might save a lot of troubleshooting later.

1. Is system RAM available?
2. What is your Java version?

Open the ‘Task Manager’ on Windows or ‘About This Mac’ on macOS and note your total physical memory. Trying to allocate more RAM than your system has free will crash Minecraft on startup with a Java heap error. Modern Minecraft (1.18+) also requires Java 17 or later. Recent modpacks need Java 21. The official launcher bundles the correct Java automatically. The old 32-bit cap of 2 GB only applies to ancient setups. Virtually every modern machine runs 64-bit Java, so ignore that limit unless you deliberately installed a 32-bit build.

Allocating More Minecraft RAM on GPORTAL Servers

On a GPORTAL Minecraft server there are no files to edit, no Java arguments to memorise, and no -Xmx flags to get right. The RAM is part of the plan you book. Current presets are 2 GB, 4 GB and 6 GB, plus custom configuration for heavier modpacks and bigger communities. To change the allocation after ordering:

1. Log in.
2. Open My Server.
3. Use Edit Gamecloud to upgrade or downgrade.

The change applies on the next restart. No downtime planning, no file edits, no risk of breaking a start script, and if a modpack later needs more memory, two clicks puts it there.

Client: How to Allocate More RAM to Minecraft

Changing how much RAM Minecraft uses happens at the launcher level, not inside the game. The principle is always the same: you are editing the Java argument -Xmx, which sets the maximum heap size the game is allowed to grow into.

Default Minecraft Launcher (Java Edition)

Keep in mind that the value is case-sensitive and there must be no space between the number and the G:

1. Open the Minecraft Launcher and select Minecraft: Java Edition.
2. Click the Installations tab at the top.
3. Hover the installation you want to edit, click the three dots, and pick Edit.
4. Click More Options below the resolution settings.
5. In the JVM Arguments field, find -Xmx2G and change the number.
6. Click Save and launch the game.

Bedrock Edition does not expose this setting. It manages memory dynamically and can’t be increased manually.

CurseForge, Prism Launcher & Other Third-Party Launchers

Modpack launchers expose MinecraftRAM as a simple slider. In the CurseForge App, click the gear icon, open Minecraft under Game Specific, scroll to Java Settings, and drag the Allocated Memory slider. Prism Launcher, ATLauncher, MultiMC and GDLauncher each have a similar field under their Java tab, often editable per instance. This is useful when one modpack needs 4 GB and another needs 10 GB on the same machine.

Server: Add More RAM to Minecraft

Server RAM is a separate setting from the client and matters more for multiplayer performance. The server is where the world ticks, mobs spawn, and chunks generate. There are two realistic paths, and they differ dramatically in effort: a rented host that handles the heavy lifting, or self-hosting on your own machine where you write the start command yourself.

Self-Hosted Minecraft Server (Windows / Linux / macOS)

If you run a server on your own machine, Minecraft RAM is assigned through the start script in the server folder. On Windows, create a run.bat file containing:

java -Xms4G -Xmx4G -jar server.jar nogui

On Linux or macOS:

1. Save the same line as start.sh.
2. Make it executable with chmod +x start.sh.
3. Run it with ./start.sh.

Replace 4G with your target allocation in both places.

The -Xmx flag sets the maximum heap, and -Xms sets the starting heap. Setting both to the same value on a server is standard practice: it tells Java to reserve the memory up front rather than expanding mid-tick, which avoids garbage-collection stutter under load. Everything else about your server (view distance, player limit, gamemode) lives in server.properties, not in the start script. For the full self-hosting walkthrough see our Minecraft server guide.

When More Minecraft RAM Won’t Fix the Problem

Adding more RAM is the right call for memory-pressure symptoms: ‘Out of Memory’ crashes, missing chunks, freezes during chunk loading. It is the wrong call for the other common Minecraft performance problems.

Minecraft is heavily single-threaded on the server side: the main tick loop runs on one CPU core, so once the world’s logic exceeds what that core can handle in 50 ms, you get low TPS no matter how much Minecraft RAM is available. Log messages like ‘Can’t keep up! Is the server overloaded?’ point to a CPU bottleneck, not a memory one. The fix in those cases is performance plugins (Paper, Pufferfish), pre-generating chunks, or profiling with Spark. Network-level issues like the ‘Connection Timed Out’ error also have nothing to do with RAM and need a different fix entirely.

FAQ

Memory Made Easy – Get the Minecraft RAM Without the Riddles

Allocating more RAM to Minecraft sounds technical, but it comes down to one Java argument and one good number. Pick the right value for your setup, edit one line in your launcher or start script, and the crashes and stutter usually disappear. The trickier part is knowing how much memory the situation actually calls for. If you would rather skip the JVM arguments altogether, a Minecraft server from GPORTAL handles the RAM, the Java version and the startup parameters for you. Pick a plan, hit start, and the server is online in under three minutes. Upgrade or downgrade your Minecraft RAM tier at any time from the web interface, no downtime planning and no file editing required. More memory, fewer riddles, let’s go.

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