In this lesson, you will learn how to leverage the Unreal Insights Network Profiler to pinpoint specific actors that are saturating your network bandwidth.
Visualizing Network Throughput
When your game experiences hitches or bandwidth spikes, it is rarely due to a "slow" network in the abstract; it is almost always caused by specific actors replicating too much data or updating too frequently. The Network Profiler within Unreal Insights allows you to move beyond guessing by providing a granular timeline of exactly which packets contain what data.
To get started, you must first capture trace data. Launch your game with the command-line argument -trace=net. Once your session is recorded, open the .utrace file in Unreal Insights and navigate to the Network Profiler tab.
Identifying the Culprits
Once the data is loaded, look at the Packet View. You will see a breakdown of outgoing traffic. By selecting a high-traffic frame in the timeline, you can inspect the Actor List panel. This displays every actor that sent data during that specific packet:
- NetGUID: The unique identifier for the actor.
- Property Count: How many properties were dirtied and serialized.
- Payload Size: The total bits consumed by that actor in this specific packet.
If you find a specific character or manager class consistently occupying the largest slice of the pie, you know exactly where to apply optimizations like NetUpdateFrequency adjustments or migrating data to Fast TArray replication.
Analyzing Property Updates
The most powerful feature is the ability to drill down into the Property view for a selected actor. You can literally see which variables are triggering the most frequent replications. For example, if you are replicating a float representing a health value that changes every tick, the profiler will highlight that property as a "hot" item. Seeing this data makes it obvious why your bandwidth is high:
// If the profiler shows this property is bloated:
UPROPERTY(Replicated)
float HighFrequencyData; // Perhaps this shouldn't replicate every frame?
By identifying these "bandwidth hogs," you can surgically target your replication logic rather than blindly lowering network settings across your entire project.
Key Takeaway: The Network Profiler transforms raw traffic data into actionable insights, allowing you to identify specific actors and properties that exceed your bandwidth budget.