The official launcher gives Minecraft 2 GB of memory by default. That is enough for vanilla, tight for vanilla with high render distance, and not enough for most modpacks. Changing it takes one line.
This guide is for playing Minecraft on your PC. Running a server is a different question, covered in how much RAM a Minecraft server needs.
RateVanilla: 2-4 GB, modded: 6-8 GB
XP levelOne setting
Build time2 minutes
DifficultyBeginner
How much RAM to give
| Your setup |
Allocate |
| Vanilla, render distance up to 12 |
2 to 4 GB |
| Vanilla, high render distance or shaders |
4 GB |
| Light mods (Sodium, Iris, a few utilities) |
4 GB |
| Medium modpacks (around 100 mods) |
6 GB |
| Large modpacks (200+ mods, big tech packs) |
8 GB |
Two limits matter more than the table:
- Never give more than about half of your PC's total RAM. Windows, your browser, Discord and the Java process itself need the rest. On an 8 GB PC, 4 GB is the ceiling.
- More is not faster. Past what the game actually uses, extra RAM does nothing for FPS, and very large values can make stutter worse (see below).
Official Minecraft Launcher
- Open the launcher and go to Installations.
- Hover over your installation, click the three dots, then Edit.
- Click More options.
- In JVM arguments, find
-Xmx2G at the start.
- Change the number, for example
-Xmx4G for 4 GB. Keep the rest of the line as it is.
- Save, then play.
-Xmx sets the maximum memory. G means gigabytes; -Xmx4096M would mean the same as -Xmx4G.
CurseForge, Modrinth App and Prism Launcher
- CurseForge: Settings, then Minecraft, then Java Settings, and move the Allocated Memory slider. Individual modpacks can override it in their profile options.
- Modrinth App: Settings, then Java and memory, and set Memory allocated. Each instance can override it in its own settings.
- Prism Launcher: Settings, then Java, and set Maximum memory allocation, or per instance under Edit instance, Settings, Java.
Modpack pages often list a recommended amount. Follow it before you follow this table.
Why too much RAM can hurt
Java cleans up unused memory in batches called garbage collection. With a huge allocation, the game lets garbage pile up for longer, then has more to clean at once, which can show up as a stutter every so often. Giving a vanilla game 16 GB is a classic way to make it run worse, not better.
If you stutter with mods, the fix is usually better garbage collection flags and performance mods, not more memory. The Aikar JVM flags guide explains the flags, and the Fabric performance mod stack covers mods that cut memory use.
How to check what Minecraft actually uses
Press F3 in game. On the right you will see Mem: the percentage of the allocated memory in use, and the amount. If it regularly climbs to 90-100% and the game freezes, you need more. If it sits around 40-60%, you already have plenty, and adding more will not help.
Common problems
- "Out of memory" crash or the game closes in a modpack. Raise the allocation by 2 GB and try again.
- The setting has no effect. You edited a different installation or profile. Check the one you actually launch.
- The game will not start after the change. You may have allocated more than your PC has, or broken the JVM arguments line. Set it back to
-Xmx2G and change only the number.
- Low FPS with plenty of free memory. RAM is not the bottleneck. Start with the lag and stutter guide or the complete performance guide.
Frequently asked questions
How do I allocate more RAM to Minecraft?
In the official launcher: Installations, Edit, More options, then change -Xmx2G in JVM arguments to -Xmx4G (or the amount you want).
How much RAM should I give Minecraft?
2 to 4 GB for vanilla, 4 GB with shaders or light mods, 6 to 8 GB for modpacks. Never more than about half of your PC's total memory.
Does more RAM increase FPS?
Only if the game was running out of memory. Otherwise FPS depends on your GPU, CPU and settings, and too much RAM can cause stutter.
What is the default RAM for Minecraft?
The official launcher allocates 2 GB by default.
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