How much RAM should you give Minecraft and modpacks?
A practical table of how much memory to allocate to vanilla Minecraft and modpacks of every size, and why giving it more than it needs makes it slower.
By Elchi, maker of Alloy. Updated . 4 min read.
Give vanilla Minecraft 2 GB, a light modpack (up to 30 mods) 3 GB, up to 100 mods 4 GB, up to 200 mods 6 GB, and bigger packs 8 GB. Never give it more than half of your PC's memory. More than the pack needs doesn't make it faster and can cause longer stutters.
How much to allocate
| What you play | Memory to allocate |
|---|---|
| Vanilla, or only performance mods | 2 GB |
| Up to 30 mods | 3 GB |
| 31 to 100 mods | 4 GB |
| 101 to 200 mods | 6 GB |
| More than 200 mods | 8 GB |
These are the amounts Alloy recommends for each instance, capped at half your RAM. Add 1 to 2 GB for shader packs, very high render distances or large resource packs.
Why more isn't better
The number you set is the maximum size of Java's heap, where the game keeps its objects. Java cleans that heap up in the background, and a bigger heap holds more garbage to sort through. Allocate far more than the pack uses and the clean-ups get rarer but longer, which shows up as stutters. Allocate too little and the game cleans up constantly, which shows up as low FPS, and finally crashes with OutOfMemoryError.
Minecraft also uses memory outside the heap, for the game's native code, graphics and Java itself, so the real usage in your task manager is higher than the number you set.
Leave memory for your PC
Windows or Linux, your browser, Discord and the launcher need memory too. Alloy lets you allocate up to your total memory minus a reserve: 2 GB on PCs with up to 8 GB, 3 GB up to 16 GB, and 4 GB above that. It warns before the system would run short.
- 8 GB of RAM: up to 6 GB for Minecraft; 4 GB is the comfortable choice for a modpack.
- 16 GB: up to 13 GB; 6 to 8 GB covers almost any pack.
- 32 GB or more: up to everything but 4 GB, though very few packs benefit from more than 10 GB.
Setting it in Alloy
Open the instance, go to Settings and drag the memory slider. The recommended amount for that pack's mod count is marked on the slider, and Alloy warns when an amount would leave your system short.
Alloy does this for you. It checks every mod before Minecraft starts and offers a fix for each problem. It's free for Windows and Linux. Download Alloy