
Light Core
LightCore is a client-side performance monitor that samples FPS and system memory/CPU usage, logs results, and ranks your Minecraft performance with tiers and insights.
About this Mod
LightCore
LightCore is a lightweight, client-side performance logger for Minecraft that samples FPS and key system metrics, then converts them into a clear score, tier, and ranking—so you can understand what’s driving low performance.
What it measures
LightCore collects periodic performance snapshots containing:
- Client FPS (averaged over a short rolling window)
- JVM memory usage (heap used / heap max)
- Physical memory usage (used / total)
- CPU load (percent) and CPU core count
- OS/architecture/Java version metadata (for context)
Scoring, tiers, and ranking
Each snapshot is analyzed into:
- Score (0–100): a weighted evaluation based on FPS plus penalties from memory pressure, CPU load, and CPU core context
- Tier:
Excellent,Good,Average, orLow - Hint: a short, actionable message (e.g., low FPS, high CPU load, or high memory pressure)
- Rank: where the current snapshot stands compared to recent history
Sampling timing adapts to current conditions (when FPS is low, it samples more frequently; when FPS is stable, it backs off).
Output (CSV + logs)
Results are written to your local game directory as a CSV file:
logs/lightcore-performance.csv
It also prints a compact summary line to logs for quick checks while testing.
How to use
- Install the mod on the client.
- Play normally for a few minutes (especially when you suspect lag/stutter).
- Review
lightcore-performance.csvand the log output to spot trends and the best/worst snapshots.
Compatibility
Designed for Fabric with Fabric API and runs on the client side.
Available Versions
How to Install Light Core on Your Client
Install the Mod Loader Locally
Install fabric for your local Minecraft version.
Download the Matching File
Choose the Light Core file for fabric and Minecraft 1.21.11.
Install Mod
Place the .jar file in your local .minecraft/mods folder and restart Minecraft. No server-side installation is required.
Compatibility
Mod Loaders
Minecraft Versions
1.21.11, 1.21.10, 1.21.9 (+5 more)
Server-side
✗ UnsupportedRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
Does Light Core need to be installed on the Minecraft server?
No. Modrinth marks Light Core as unsupported on the server side. Install it only in your local Minecraft mods folder. Your server can remain unchanged unless the mod page lists an additional dependency.
Which version and loader does Light Core require?
Use a file for fabric and your exact Minecraft version. Supported versions include 1.21.11, 1.21.10, 1.21.9. Files for different loaders are not interchangeable.
Light Core is not working – what should I check?
First check the Minecraft version, loader version and required dependencies. Put the .jar file in your local .minecraft/mods folder and remove older duplicates. Because this mod is client-side, adding server RAM will not fix it.
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