Minecraft Java Edition can use more system memory when you run large modpacks, shaders, high-resolution resource packs, or heavily modded Forge installations. If the game suffers from stuttering, crashes, or out-of-memory errors, increasing the allocated RAM may help.
However, giving Minecraft as much RAM as possible is not always the best solution. Mojang currently recommends keeping Minecraft’s allocation within a sensible portion of your system memory, and its latest Java Edition guidance notes that up to half of total RAM is the recommended maximum.
How to Allocate More RAM to Minecraft
If you use the official Minecraft Launcher, you can change the game’s memory allocation through the installation settings.
Step 1: Check Your System RAM
Before changing anything, check how much RAM your PC has.
On Windows, go to:
Settings → System → About
Mojang recommends checking your installed memory first because the available RAM determines how much you can safely allocate to Minecraft.
Step 2: Open Minecraft Launcher
Launch the official Minecraft Launcher and select Minecraft: Java Edition.
Then:
- Open the Installations tab.
- Find the Minecraft version you want to modify.
- Click the installation’s three-dot menu.
- Select Edit.
- Open More Options.
You should now see the JVM Arguments field.
Step 3: Change the -Xmx Value
Look for an argument similar to:
-Xmx2G
The -Xmx value determines the maximum amount of RAM Java can use for Minecraft.
For example:
- -Xmx2G = maximum 2 GB
- -Xmx4G = maximum 4 GB
- -Xmx6G = maximum 6 GB
- -Xmx8G = maximum 8 GB
To allocate 4 GB, change the relevant value to:
-Xmx4G
Save the installation before launching the game. Mojang specifically recommends backing up the existing JVM arguments before making changes so you can restore them if something goes wrong.
How Much RAM Should Minecraft Get?
More RAM does not automatically mean more FPS.
For a lightly modded or vanilla game, 2-4 GB may be enough. Larger modpacks can benefit from 6-8 GB, depending on the number and type of mods.
As a general starting point:
| System RAM | Minecraft Allocation |
| 8 GB | 3-4 GB |
| 16 GB | 4-8 GB |
| 32 GB | 6-12 GB |
| 64 GB | 8-16 GB |
These are starting points rather than strict requirements. Leave enough memory for Windows, background applications, your launcher, and other programs.
Mojang currently recommends no more than roughly half of total system RAM for Minecraft’s allocation.
How to Allocate More RAM to Forge
Forge uses Java, so the same -Xmx JVM argument controls the maximum heap memory when you launch a Forge installation through the Minecraft Launcher.
Open:
Minecraft Launcher → Installations → Forge → Edit → More Options → JVM Arguments
Find the -Xmx value and increase it.
For example, if your Forge profile contains:
-Xmx2G
you can change it to:
-Xmx6G
if your system has enough available memory.
Forge community guidance also confirms that -Xmx controls maximum RAM, while -Xms controls the initial or minimum heap allocation.
How Much RAM Does a Modded Minecraft Pack Need?
The right amount depends heavily on the modpack.
Small Forge modpacks may run comfortably with 4 GB, while larger packs containing hundreds of mods, expanded world generation, automation systems, or large structures may require 6-10 GB or more.
Avoid immediately assigning 12-16 GB simply because your PC has 16 or 32 GB. Excessive allocation can leave too little memory for the operating system and other applications, potentially creating additional performance problems.
Does More RAM Increase Minecraft FPS?
Not necessarily.
RAM allocation mainly helps Minecraft avoid memory-related problems. If your game already has enough memory, increasing it further may produce little or no FPS improvement.
Low FPS is often caused by the CPU, GPU, render distance, shaders, simulation distance, graphics settings, or poorly optimized mods.
More RAM becomes particularly useful when you experience out-of-memory crashes, heavy stuttering, long loading times, or modpacks that exceed the current allocation. Minecraft’s official troubleshooting guidance specifically connects inappropriate memory allocation with crashes, lag, and stuttering.
Minecraft RAM Allocation Not Working?
If changing -Xmx does not appear to work, check the JVM arguments carefully. Make sure there is not another -Xmx value later in the arguments overriding your setting. Forge forum discussions have documented cases where a later -Xmx value takes precedence.
If Minecraft refuses to launch after changing the setting, restore your original JVM arguments. Mojang also recommends creating a fresh Java installation when troubleshooting launcher or installation problems.
Conclusion
Learning how to allocate more RAM to Minecraft is useful when running demanding Forge modpacks or experiencing memory-related crashes. For most players, the best approach is to increase memory gradually rather than assigning as much RAM as possible.
Start around 4 GB, test your game, and increase the allocation only if your particular modpack needs more. Most importantly, keep sufficient RAM available for Windows and other applications so your entire PC remains responsive.
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