GPU performance testing guide for Volume Shader workloads
Volume shaders make useful browser benchmarks because they create repeatable GPU pressure. A single frame may run dozens or hundreds of ray steps for every pixel. Add fractal math, density sampling, lighting, and high resolution, and the workload quickly reveals how a device handles WebGL shader pressure.
The GPU performance test uses that idea. Each level increases the per-pixel cost so you can see where a device moves from smooth rendering into unstable frame time.
What the test measures
This benchmark focuses on fragment shader throughput. It does not replace every desktop benchmark, but it is highly relevant for browser shader art, live WebGL tools, and volume rendering experiments.
| Level | What increases | What it reveals |
|---|---|---|
| Light | Basic ray marching | WebGL compatibility |
| Medium | More samples | Entry GPU comfort |
| Heavy | More field evaluation | Mainstream GPU headroom |
| Extreme | Dense marching | Sustained performance |
| Ultra | Very high per-pixel cost | Stress stability |
Why frame time matters
Average FPS is easy to read, but it can hide stutter. A test that averages 60 FPS with frequent spikes can feel worse than one that holds a lower but stable rate. Frame time shows the cost of each frame directly.
Shader frame-time spikes usually come from too many ray steps, expensive nested loops, divergent branches, browser overhead, or thermal throttling. If a shader feels uneven, reduce ray steps first and watch whether the frame-time trace calms down.
How to use the result
Use the highest stable level as a rough guide. Level 1 comfort is enough for simple smoke and backgrounds. Level 3 comfort is good for editor experiments and cloud layers. Level 5 stability suggests headroom for advanced fractals and large displays.
Then open the editor and tune your shader with the same logic: control steps, iterations, resolution, and early exits. A fast shader is not the one with the most samples. It is the one that spends samples where the viewer can see them.
