How Much RAM for Modded Minecraft (and How to Allocate It)

The right values for each pack size

Launchers set RAM in megabytes: 4 GB = 4096 MB, 6 GB = 6144 MB, 8 GB = 8192 MB. Here are the ranges most players agree on in 2026:

• Light pack (under 100 mods, optimization packs, standalone Create, most lightweight Fabric packs): 4 GB is enough.
• Mid-size pack (100 to 200 mods, RLCraft, most quest packs, Create Astral or Above & Beyond): 6 to 8 GB.
• Heavy kitchen-sink pack (250+ mods: All The Mods 9 or 10, DeceasedCraft, big custom packs): 8 to 10 GB, occasionally 12 GB for the heaviest.
• Safety rule: never allocate more than half of the machine’s physical RAM — the OS, the launcher and your browser need the rest. With 16 GB total, cap the allocation at 8 GB.

The “too much RAM” trap and the garbage collector

A common but wrong intuition: allocating as much RAM as possible does not make the game faster. Java runs a garbage collector that periodically cleans up used memory: the larger the allocated space, the more memory each cleanup churns through at once — and beyond roughly 12 GB, those pauses become noticeable in game as regular micro-freezes, even on a powerful machine.

Extra RAM only helps if you were actually running out. Real smoothness gains come from elsewhere: the performance mods bundled in recent packs, a fast CPU (Minecraft remains largely single-threaded), and an allocation simply matched to the pack’s size. If the game runs well on 8 GB, bumping it to 12 will do nothing good.

Allocating RAM in the CurseForge App

1. 1

   Open the Minecraft settings

   Click the gear icon (Settings) in the bottom-left corner of the app, then click Minecraft under Game Specifics in the left column.

2. 2

   Set the memory slider

   Scroll down to Java Settings and drag the Allocated Memory slider to the value you want (6144 MB for 6 GB, 8192 MB for 8 GB). The setting saves automatically and applies to all your packs.

3. 3

   Adjust a single pack (optional)

   To give more RAM to one heavy pack only, open the three-dot menu next to its Play button, choose Profile Options, untick the box that inherits the system memory settings, and set that pack’s own slider.

4. 4

   Restart the game

   The new allocation only takes effect on the pack’s next startup. Relaunch and check how the game feels.

Allocating RAM in Prism Launcher

1. 1

   Set the global value

   Open Settings, then the Java tab: the Maximum memory allocation field sets the RAM for every instance without its own override. Enter the value in MB, for example 8192.

2. 2

   Or set a single instance

   Right-click the instance, choose Edit, go to Settings, then the Java tab: tick the Memory checkbox to decouple the instance from the global settings, then adjust Maximum memory allocation for that pack only.

3. 3

   Let Prism handle Java

   Prism downloads and selects the right Java version per instance automatically: do not hand-edit JVM arguments unless you have a specific need — a properly sized allocation covers the vast majority of cases.

Spotting too little (or too much) RAM

The symptoms of too little RAM are unmistakable: crashes with an OutOfMemoryError or Java Heap Space message, endless world loading, heavy stutter whenever you explore new chunks. In that case, raise the allocation one step (from 6 to 8 GB, for example) and relaunch.

Too much RAM shows up differently: the game runs smoothly overall but freezes for a fraction of a second at regular intervals — the signature of long garbage collector pauses. Bring the allocation back down to the recommended tier for your pack. And if the stutter persists no matter the allocation, the bottleneck is likely the CPU or the server, not your memory.