Close Minecraft and any launchers you don’t need
Open your Minecraft launcher
Go to Installations
Select the instance you want to change
Click Edit
Find JVM Arguments or “More Options”
Increase the maximum RAM value in the JVM arguments (example: `-Xmx4G`)
Set `-Xms` to a matching or smaller value (example: `-Xms2G`)
Keep JVM arguments like:
`-Xms2G -Xmx4G`
Save changes
Launch the selected installation
If using the official launcher and you don’t see JVM Arguments, add them under “More Options”
If you use a third-party launcher (e.g., MultiMC/Prism/ATLauncher), open its instance settings
Look for Memory/RAM/Java settings
Set the maximum RAM for the instance (example: 4096 MB)
Apply/save changes
Restart the launcher and start the game
Verify in-game by checking debug/performance info (or logs) if needed
Avoid setting RAM higher than available system memory (leave room for the OS and background apps)