Prism Launcher Technical Glossary
Clear definitions of Minecraft modding and launcher terms: `.mrpack`, Fabric vs NeoForge, JVM heap flags, G1GC/ZGC, and Exit Code 1.
JVM Heap Memory (-Xms and -Xmx)
The minimum (`-Xms`) and maximum (`-Xmx`) system RAM in MiB that Java is allowed to allocate for Minecraft.
- Term
- JVM Heap Memory (-Xms and -Xmx)
- In Short
- The minimum (`-Xms`) and maximum (`-Xmx`) system RAM in MiB that Java is allowed to allocate for Minecraft.
- Applies To
- Prism Launcher on Windows 10 & 11
Definition: JVM Heap Memory (-Xms and -Xmx)
The minimum (`-Xms`) and maximum (`-Xmx`) system RAM in MiB that Java is allowed to allocate for Minecraft.
Configure memory globally in Prism Launcher Settings → Java or override it per instance under Edit Instance → Settings → Memory.
How Prism Launcher handles this on Windows
Every instance in Prism Launcher exposes its version stack, mod list, resource packs, shader packs, and JVM settings in one clean Edit Instance window.
Grab the latest Windows installer or portable ZIP from /download to manage all your Minecraft versions in one place.
Frequently asked questions
What does JVM Heap Memory (-Xms and -Xmx) mean in Prism Launcher?
The minimum (`-Xms`) and maximum (`-Xmx`) system RAM in MiB that Java is allowed to allocate for Minecraft. Configure memory globally in Prism Launcher Settings → Java or override it per instance under Edit Instance → Settings → Memory.
Where can I configure this inside the launcher?
Right-click any instance on the Prism Launcher dashboard and select **Edit** (or open global **Settings** on the top toolbar).
Get Prism Launcher
Windows, macOS & Linux
Free and open source. Sign in with the Microsoft account that owns Minecraft, then create your first instance.
