Free GPU Stress Test - WebGL Fragment Shader Benchmark

GPU Stress Test

Renders a high-iteration Mandelbrot fragment shader every frame, scaling canvas size and quality to push any GPU from integrated laptop to desktop RTX. Reports live FPS, stability, GPU vendor/renderer when available, and whether WebGL2 is software-rendered (SwiftShader fallback). Includes a thermal warning — sustained runs will heat a laptop.

Stress settings

Iterations1500

Resolution1.0x

Warning: high iteration counts on integrated laptop GPUs can pull the system hot quickly. If you see major stutter or the browser tab crash, lower iterations and resolution and retry.

Live results

—FPS (instant)

—FPS (1s avg)

0Frames

0Elapsed (s)

—Min FPS

Waiting to initialize WebGL2...

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GPU Stress Test guide

How to use the GPU Stress Test accurately

The test uses WebGL2 to render a full-screen Mandelbrot fragment shader every frame. For each pixel, the fragment shader runs an iterative complex-number escape calculation with an adjustable loop count (up to 5000 iterations).

01 How The GPU Stress Test Works The test uses WebGL2 to render a full-screen Mandelbrot fragment shader every frame. For each pixel, the fragment shader runs an iterative complex-number escape calculation with an adjustable loop count (up to 5000 iterations).

02 Detecting Software Rendering One of the most useful things this test exposes is whether your browser is actually using the GPU. Chrome, Firefox, and Safari all ship with software-rendering fallbacks (SwiftShader on Chrome, llvmpipe on Linux, Core Graphics...

03 Reading The FPS Numbers The instantaneous FPS shows the last frame's delta, which is noisy; the 1-second rolling average smooths that into a usable number.

04 Why GPU Vendor Info Is Often Hidden Chrome began masking GPU vendor and renderer strings in 2020 as part of an anti-fingerprinting push. On a default Chrome install, WEBGL_debug_renderer_info returns generic values like "Google Inc.

gpu stress test webgl benchmark gpu load test fragment shader test browser gpu test graphics card stress

One of the most useful things this test exposes is whether your browser is actually using the GPU. Chrome, Firefox, and Safari all ship with software-rendering fallbacks (SwiftShader on Chrome, llvmpipe on Linux, Core Graphics fallback on older Macs) that kick in when hardware...

GPU Stress Test FAQ

Common gpu stress test questions

Why is my GPU vendor shown as "hidden"?

Chrome redacts WEBGL_debug_renderer_info by default as an anti-fingerprinting measure. Firefox does the same under privacy.resistFingerprinting. To see the real vendor/renderer, visit chrome://gpu in Chrome or look up your GPU in the OS hardware panel.

What does "SwiftShader" or "llvmpipe" mean?

Those are software WebGL renderers that run on the CPU when hardware acceleration is unavailable. If you see them in the renderer string, your browser is not actually using your GPU. Re-enable hardware acceleration in browser settings and update your GPU driver to restore real performance.

Can I damage my GPU with this test?

On stock hardware, no. GPUs throttle their clock and voltage well before thermal damage, and modern drivers monitor junction temperature. On manually overclocked GPUs, sustained load (10+ minutes) can expose an unstable clock that was fine on short benchmarks. Stop if you see artifacts, crashes, or driver resets.

Why do my FPS drop 30-50% after 30 seconds?

Thermal throttling. The GPU is hitting its thermal envelope and dropping clock speed to stay cool. Laptops show this dramatically; desktops with good cooling usually hold steady. If you want steady numbers, improve airflow, re-paste the GPU if it is 3+ years old, or run shorter bursts.

Checklist

Utility checks to confirm

How The GPU Stress Test Works The test uses WebGL2 to render a full-screen Mandelbrot fragment shader every frame. For each pixel, the fragment shader runs an iterative complex-number escape calculation with...
Detecting Software Rendering One of the most useful things this test exposes is whether your browser is actually using the GPU. Chrome, Firefox, and Safari all ship with software-rendering fallbacks...
Reading The FPS Numbers The instantaneous FPS shows the last frame's delta, which is noisy; the 1-second rolling average smooths that into a usable number.