CPU Stress Test
Push your CPU to maximum load to check stability, validate overclocks, and monitor thermal performance. Runs entirely in your browser — no download needed.
What will happen
The test will run JavaScript loops in background threads to max out your CPU. Your fan may spin up. The test stops automatically when the timer runs out, or you can stop it at any time.
Test Configuration
* = max (32 logical cores detected)
Live Metrics
Watch your temps. Stop the test if your CPU exceeds 90°C. Ensure your cooling is adequate before running long tests.
What is a CPU Stress Test?
A CPU stress test pushes your processor to 100% utilisation to check stability, validate cooling performance, and identify thermal throttling. It is an essential step after overclocking, building a new PC, or diagnosing system instability.
CPUKiller's browser-based stress test uses JavaScript Web Workers to generate genuine CPU load across one or more threads. Unlike desktop tools such as Prime95 or AIDA64, no download or installation is required — the test runs entirely in your browser.
For best results, run the stress test for at least 10–15 minutes while monitoring CPU temperatures with a tool like HWiNFO or Core Temp. If temperatures exceed 90°C, your cooling solution may be inadequate.