How to Test a GPU?

Prepare the device

Background work steals GPU time. So does leftover heat from a game. Do this before you open a live test. On a laptop, note whether the charger is in. Battery mode often cuts clocks. On a phone, take the case off if you plan a long hold.

• Close extra tabs, overlays, and screen recorders until you are ready to capture
• Turn off battery saver or low power
• Let the device cool five to ten minutes after heavy use
• Note the browser and whether the laptop is plugged in
• On phones, start Volume Shader at Standard, not Extreme

Pick the matching load

The four live canvases are listed on live GPU tests. Open one canvas. Do not average all four.

• Quick visual check: Volume Shader at Standard
• General graphics card check: 3D test at Medium with a one minute timer
• Fragment pressure: shader test
• Texture sampling: VRAM test
• Heat and throttling: GPU stress test
• Two devices, fair score: GPU benchmark

Run and record

Watch the typical FPS, not only the first second. If the number falls after a minute, the device is throttling. Write down the level and the browser. Repeat once after a short cool down if you plan to compare. On the 3D test the timer prints average FPS, min FPS, and a verdict when it ends.

If FPS sticks to 60 or 120, the display is the cap. Raise the level until the counter drops. That drop is the GPU.

GPU health check, what FPS cannot tell you

Live FPS is not a diagnostic of dying VRAM, artifacting drivers, or a counterfeit SoC. Artifacts, crashes, or temperatures from a hardware monitor are different tools. On Windows that often means GPU-Z or HWiNFO. Task Manager and Activity Monitor show process load, not a graphics score.

If the canvas never starts, try another browser or check that WebGL is on. That is a software path, not a death certificate for the GPU. Reading the number: what FPS means.