Lag Detective
Lag Detective is a lightweight diagnostics mod that helps answer where the lag is coming from.
About this Mod
LagDetective
**Lag Detective is a lightweight Fabric diagnostics mod for Minecraft that helps you quickly understand why your game or server is lagging — without installing heavy profilers or complex tools.
It provides real-time performance monitoring, clear lag classification, and easy-to-read reports through simple commands and an optional client dashboard.**
What Lag Detective Does:
Lag Detective helps answer questions like:
- Is the lag coming from the server TPS or the client FPS?
- Are you CPU/tick bound, GPU/render bound, or memory/GC stuttering?
- Are too many entities loaded in one chunk?
- Is chunk loading or world generation causing spikes?
- What are the most likely causes right now?
Key Features:
Server Performance Tools:
- TPS and MSPT monitoring
- Entity and chunk activity tracking
- Server-side lag diagnosis
- Support report generation
Client Diagnostics Dashboard
- FPS + frame time monitoring
- Client tick time measurement
- Memory + GC spike detection
- Server metrics shown when available
Commands:
/ld status — server performance summary
/ld fps — current client FPS
/ld mspt — server tick time
/ld tps — server TPS estimate
/ld clientinfo — full client debug info
/ld serverinfo — full server debug info
/ld entity — chunk-by-chunk entity scan
/ld report — generate support report
/ld ui — open the diagnostics dashboard
Support Reports
Lag Detective can generate a complete diagnostic report for debugging or support requests:
- System + mod info
- Current TPS/FPS/MSPT
- Top lag causes with confidence scores
- Recommended actions
- Saved automatically as:
lagdetective-report.txt
Designed for Safety & Compatibility
- Works on client + dedicated server
- No mixins required
- Lightweight sampling (default once per second)
- Never modifies other mods or game settings
- Suggestions are informational only
Perfect For:
- Server owners tracking TPS drops
- Modpack developers diagnosing performance
- Players experiencing stutters or frame lag
- Debugging mob farms, chunk loaders, or heavy mods
Lag Detective: Find the cause. Fix the lag. Play smoothly.
Available Versions
How to Install Lag Detective on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set fabric Loader
In the panel under "Egg", select the fabric loader and matching Minecraft version (1.21.11).
Install Mod
Open the mod browser in the dashboard and search for "Lag Detective". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
1.21.11
Server-side
~ OptionalRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
Lag Detective server crashes on startup – what to do?
Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21.11). You can switch loaders with one click in the panel.
Is Lag Detective compatible with fabric?
Lag Detective officially supports fabric for Minecraft 1.21.11. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with Lag Detective – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Lag Detective consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
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Rent Modded Server
Install Lag Detective with just one click on your server.