CPU Stress Test
Run a configurable, cancellable CPU workload in Web Workers and observe throughput and stability.
Test interface
Your browser may ask for permission after you press Start.How to use this tool
- Choose a duration and worker count, then read the heat and battery warning.
- Click Start stress test and keep the device ventilated.
- Watch worker throughput and elapsed time; the test stops automatically at the chosen duration.
- Use Stop immediately if the device becomes uncomfortably hot or unstable.
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Technical explanation
Web Workers run integer and floating-point loops off the main thread, keeping the interface responsive. Throughput is the number of completed operations per second across workers.
A browser workload is not a calibrated CPU benchmark. Thermal throttling, background tasks, browser scheduling, and device power limits make results unsuitable for comparing different devices. Stop immediately if the device overheats.
Troubleshooting
Device becomes very hot
Stop the test. Thin laptops and phones may throttle quickly. Allow the device to cool before another run.
Fewer workers than requested
The browser may limit worker count or available memory.
Test stops early
Some mobile browsers suspend background tabs. Keep the page visible and the screen on.
Throughput drops over time
Thermal throttling or battery saver is likely. This is an observation, not a fault diagnosis.
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Frequently asked questions
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