How to allocate RAM to Minecraft

Giving Minecraft more RAM is easier than it sounds. The memory limit is one argument on the profile you launch. It looks like -Xmx2G. That number is the most memory Minecraft can use. Raising it stops out-of-memory crashes, but it won’t give you more FPS. For that, see how to increase FPS.

I play Minecraft 1.21.1 on NeoForge: Create 6, Aeronautics, and the rest of the Create Aeronautics pack. The launcher row that starts that instance is the row you edit. Latest Release is the wrong row.

How much the PC can spare

On Windows, open Settings, then System, then About, and read Installed RAM. Give Minecraft about half of that, so the rest of the computer still runs. A PC with 8 GB cannot give the game 8 GB. If the game stutters more after the change, you gave it too much. Lower the number and test again.

My PC has 32 GB of RAM, and even so, giving Minecraft more than it needs doesn’t add frames. Extra heap still does not buy frames. Sodium is the renderer. Performance mods. Java clears unused memory in pauses; a much larger allowance is what those guides say makes the pauses longer.

How much to give it

A plain game sits around 2 to 4 GB. A modest modpack sits around 4 to 6 GB. A large one sits around 6 to 8 GB, and only when the PC has the memory to spare.

Create contraptions and world-gen hitch for other reasons. spark on the server (/spark profiler) is the tick, not this slider. Server hosting.

The official launcher

Open the Minecraft Launcher and the Installations tab. Hover the profile you play, click the three dots, and choose Edit. Click More Options. In JVM arguments, change only the number in -Xmx. The guides show -Xmx2G as the line already there, which is 2 GB. -Xmx4G is 4 GB. If the line is in megabytes, 1024 MB is about 1 GB, so 4 GB is 4096. Leave every other argument on that line. Save, and launch that same profile.

A Fabric or NeoForge installation is not Latest Release. Changing the vanilla row leaves the modded game on the old number. Edit the row whose name matches the loader on the title screen.

CurseForge, Prism, Modrinth

In the CurseForge app, open the gear, then Minecraft, then the allocated-memory slider under Java settings. The slider is in megabytes. It writes the same -Xmx argument. A profile that overrides the app setting ignores the slider.

Prism keeps a minimum and a maximum under Settings, then Java, in megabytes. The maximum is the number F3 reports.

We share the Create pack through the Modrinth App. That app has its own memory box per instance. Set the number in one place. Two launchers pointing at one folder is how you lose a world — keep a modded world from breaking.

Check the Mem line

Start the profile you edited and load a world. Press F3. The Mem line at the top right should show a higher maximum, in the range you set. A line that still reads about 2048 MB means this profile was not the one you changed.

A server’s memory box belongs to the host. Set the number on the profile you actually launch, check it with F3, and you’re done.

Related: Minecraft guides, Best Minecraft mods (2026), PC builds, Java snapshot news.

Common questions

How do I allocate more RAM to Minecraft?

In the Minecraft Launcher, go to Installations, click the three dots on your profile, choose Edit, then More Options. Change the number in -Xmx (for example -Xmx6G) and save.

How much RAM should Minecraft get?

About 2 to 4 GB for vanilla and 6 to 8 GB for a big modpack. Don't give it more than about half your PC's total RAM.

Does more RAM increase FPS in Minecraft?

No. Enough RAM stops crashes and stutters, but too much can actually cause lag spikes. For more FPS, install Sodium and lower render distance.

How do I check how much RAM Minecraft is using?

Press F3 in a world and look at the Mem line in the top right corner.