What this measures
The cube benchmark is the 3D reading: many small wireframe cubes transformed in a vertex shader. There is no scene graph and no lighting model.
How to read it
Leave the canvas on screen. A frame rate from a visible canvas is the honest one. If the renderer string later says SwiftShader or llvmpipe, the draw did not use a graphics chip.
What it cannot do
Browsers can hide the chip name or fall back to software. WebGPU is absent on many engines. Frame rate also depends on this tab, the power mode, and the size of the canvas.
Questions
Is the frame rate my GPU score?
It is the frame rate of the scene on this page. Another scene, another size, or software rendering changes it.
What does SwiftShader mean?
Drawing is being done in software on the processor. The page is honest about that. It is not a broken benchmark.
WebGPU says unsupported. Is that a fail?
No. The compute page has nothing to time. Support is a yes or no.