Lag Visualizer
See what actually caused your lag spike!
(Note: Any features seen here but not in game will be added at some point. I made this description before the mod lol.)
Lag Visualizer is a lightweight client-side performance diagnostic mod for Minecraft that helps you understand why your game stutters, freezes, or suddenly drops frames.
Instead of only showing FPS, Lag Visualizer monitors frame times and other performance metrics in real time, detects major stutters, and analyzes what was happening when they occurred.
Features
Detects significant frame-time spikes
Tracks FPS, frame time, memory usage, entities, chunks, and more
Identifies likely causes of stutters
Uses confidence-based diagnostics rather than pretending every result is certain
Shows optional lag-spike notifications
Includes a compact performance overlay
Records recent stutters for later inspection
Displays frame-time history and graphs
Exports diagnostic reports for troubleshooting
Designed to have very low performance overhead
What Can It Detect?
Lag Visualizer can attempt to identify stutters related to:
Chunk loading
Chunk rebuilding
Garbage collection
High memory usage
Large entity counts
Block entities
Particle load
Resource reloads
Rendering load
Unknown or unclassified spikes
For example:
143 ms stutter
Likely cause: Chunk Loading
Confidence: 87%
Diagnostics are based on the performance data collected around each spike, so causes are shown as estimates rather than guaranteed answers.
Performance Dashboard
Open the Lag Visualizer dashboard to view information such as:
Current FPS
Current frame time
Average FPS
1% low FPS
Memory usage
Loaded chunks
Entity count
Block entity count
Session stutter count
Recent frame-time history
Detected spikes are marked on the graph so you can see exactly when performance problems happened.
Stutter History
Lag Visualizer keeps a history of recent performance spikes.
Each event can include:
Exact frame duration
Time of the spike
Suspected cause
Confidence level
Relevant performance metrics
Diagnostic explanation
This makes it much easier to investigate recurring stutters instead of guessing what caused them.
Diagnostic Reports
Lag Visualizer can export troubleshooting reports containing useful performance information such as:
Minecraft version
Fabric Loader version
Lag Visualizer version
Java version
Memory allocation
Installed mods
FPS statistics
Recorded stutter events
Diagnostic results
Reports are designed for troubleshooting and avoid including unnecessary private information such as usernames, server addresses, access tokens, or personal filesystem paths.
Compatibility
Lag Visualizer is designed to work alongside performance mods rather than replace them.
It aims to remain compatible with mods such as:
Sodium
Lithium
FerriteCore
ModernFix
ImmediatelyFast
Iris
Entity Culling
More Culling
Compatibility may vary depending on Minecraft and mod versions.
Client-Side
Lag Visualizer is a client-side mod.
Servers do not need to install it.
Why Lag Visualizer?
Most performance tools tell you:
“Your FPS dropped.”
Lag Visualizer is built to help answer the more useful question:
“Why did my game just freeze?”
If Minecraft normally runs smoothly but randomly stutters, freezes while loading chunks, or experiences unexplained frame-time spikes, Lag Visualizer is built to help you figure out what happened.

