GPU Profiling

GPU Visualiser: Unreal Engine

Diagnosis

In this example I am using the GPU Visualiser that comes with Unreal Engine to diagnose a performance hit in a specific part of the game. The GPU draw rises rapidly entering this room at about 55m/s, running at 1920x1080 on a Geforce RTX 2060, with massive performance impact occurring from the lighting and the ray traced reflections (it equates to 66% GPU cost from these two items of the scene).

Solution

Switch reflection method from ‘Raytracing’ to ‘Screen Space’ in the relevant post processing volume. This project is not photorealistic, and real-time performance is more important that visual fidelity. Also added sphere reflection captures in this area.

Attempt to maintain the fidelity of the lighting design, however switch as many lights to Static and Moveable as the engine will allow to bake into the scene via lightmaps and improve performance.

Both of these simple alterations removed 25m/s from the GPU draw in this screenshot which is a 45% improvement in GPU performance.