Path tracing. The heaviest load a browser can put on a GPU.
A real-time global illumination load that measures GPU stability and sample throughput, in your browser.
Can my PC run path tracing in games?
Illustrative progress. Not a measurement.
Resolution
Fixed 960 × 540
Load type
Extreme compute
Render mode
Path tracing + GI
Reports
Samples/s + consistency
Samples back to back, for the whole stage.
The GPU is loaded continuously for the whole stage rather than for one sample every so often, and every sample is timed, so the cost of each sample is the measurement.
- One path per pixel per sample
- A fragment shader raymarches a signed-distance-field scene, a chrome ball rolling through a course of pillars and gates, taking one jittered path per pixel for each sample with soft shadows and a reflection bounce, and accumulating a running mean over the last few samples into a float texture. The ball moves one step per sample, so it rolls as fast as the chip traces.
- A fixed length, loaded throughout
- The stage has a fixed length, so the run keeps its length on every card, and within it samples run back to back. On a Standard run it continues until the three minutes are up; on a Deep run it lasts 40 seconds.
- Timed to completion
- Each sample pass is timed to GPU completion with a sync point, and GPU-side time is recorded where the browser exposes a timer query. The first sample, which pays for shader compilation, is excluded, and fewer than 20 measured samples means the result is not trusted.
- Fixed at 960 by 540
- The internal resolution is fixed at 960 by 540 pixels whatever the window size or device pixel ratio, so a high-density display does not quietly change the workload.
Two numbers, and what each one means.
The image on screen is refreshed at most about 30 times a second so you can watch it resolve. That display pass is presentation and is not part of the timing.
Samples per second
Samples measured divided by the active time, after the first sample, which pays for shader compilation. Higher is faster. It is comparable between your own runs at the same backend and measurement revision, and directional against anything else.
Consistency
One minus the coefficient of variation across the per-sample times, expressed out of 100. A card that delivers samples unevenly scores lower than one that is merely slow, which is the distinction a single throughput figure hides.
Validity gate
Without a valid path-tracing result, including one taken with the tab in the background, path tracing is left out of the score and the other components carry it. The report marks the score as partial, and a partial run cannot grade above B. Skipping the stage, or a fallback, cannot inflate a score.
What it does not read
No temperature, no power draw, no VRAM. The browser exposes none of them. If the tracer stalls or floating-point render targets are unavailable, the stage substitutes a flagged placeholder that scoring refuses to trust.
Illustrative progress. Not a measurement.
Hardware
What it needs. Three tiers, no fine print.
Minimum
GTX 1050 / RX 560
Completes the run. Expect a long resolve and a low samples-per-second figure.
Recommended
GTX 1070 / RX 580
Renders a clean image well within the stage, with a consistency figure worth reading.
Optimal
RTX 2060+ / RX 5700+
The figure is the cost of each sample, not how soon the image looks done.
Questions
Path tracing, answered
- How does path tracing work?
- For every pixel, a ray is fired from the camera into the scene. Where it hits a surface, it bounces in a direction chosen at random according to how that material scatters light, and it keeps bouncing until it reaches a light or is stopped. The light it collects on the way is that pixel's colour for one sample. One sample is noisy, so many are taken and averaged, and the image converges from grain to a clean result. Because every bounce is followed, soft shadows, reflections and light bleeding colour from one surface onto another all emerge on their own rather than being faked.
- What rules does path tracing follow?
- It follows the physics of light transport, usually written as the rendering equation: the light leaving a point is the light it emits plus all the light arriving from every direction, weighted by how the surface scatters it. In practice that means a few rules. Energy is conserved, so a surface never reflects more light than reaches it. Each material has a scattering function that decides where a bounce goes. Directions are chosen at random but in proportion to how likely light is to travel that way, which is called importance sampling. And paths are ended early at random, with the survivors weighted up to compensate, so the average stays correct without tracing forever.
- What is the difference between ray tracing and path tracing?
- Ray tracing is the general technique of following rays through a scene, and games usually use it for one effect at a time, such as reflections or shadows, on top of a rasterised image. Path tracing is ray tracing taken all the way: every pixel's light is computed by following full random bounce paths, so all lighting comes from one physically based calculation. It looks more correct and costs far more, which is why it makes a demanding benchmark.
- Does a browser benchmark actually use the GPU for path tracing?
- Yes. This stage runs as a fragment shader through WebGL2, which executes on the graphics card, not the processor. Each sample is timed around a blocking draw so the figure reflects the card's real cost, and the backend in use is recorded with the result.
- What is path tracing in GPU benchmarking?
- Path tracing simulates how light realistically bounces through a scene. In benchmarking it measures GPU performance under an extreme, physically-based lighting workload, far more demanding than rasterization.
- Why is path tracing harder to run than rasterization?
- Rasterization approximates lighting cheaply. Path tracing traces many light rays per pixel and accumulates samples over time, stressing shader throughput, memory bandwidth, and scene traversal continuously.
- Why does the renderer appear frozen for a few seconds?
- Before rendering, the engine prepares the scene and shaders. On first load this can briefly make the tab unresponsive; this is expected, and the run resumes automatically.
- Is a browser path-tracing score comparable to native tools?
- It is directional, not absolute. Browser results differ from native applications and depend on backend, drivers, and browser state. We disclose the backend and sample count with every result.