What Is This CPU Benchmark?
This benchmark runs a fixed, computationally heavy JavaScript workload - prime number calculations and floating-point math - and measures exactly how long your processor takes to complete it. It's a simple way to compare relative CPU performance without installing any dedicated benchmarking software.
How to Use This Benchmark
- Close other heavy applications for a more accurate, uncontested result.
- Click "Start Benchmark".
- Wait for the calculation to finish - this typically takes a few seconds.
- Note your time and score, and compare it against other devices or previous runs.
How It Works
The benchmark performs a set number of prime number checks and trigonometric calculations in a single
JavaScript thread, timed precisely with performance.now(). Because it's single-threaded
JavaScript, this reflects your CPU's single-core performance specifically - not the full multi-core power
your processor may have available for other tasks.
Your device's logical core count is also reported using navigator.hardwareConcurrency, giving
you a sense of how many threads your CPU can run in parallel, even though this particular benchmark only
exercises one.
Understanding Your Results
Lower time and a higher score both indicate better single-core performance. Because this runs inside a browser's JavaScript engine rather than as native code, absolute numbers won't match dedicated benchmarking software like Cinebench - but relative comparisons between different devices, or the same device over time, are still meaningful.
Benefits
- Quick way to compare CPU performance across devices without installing software.
- Useful for checking if thermal throttling is affecting a laptop over repeated runs.
- No account or download required.
Common Mistakes to Avoid
- Running other heavy tasks simultaneously - this will slow down your score regardless of your CPU's actual power.
- Comparing scores across different browsers - JavaScript engine differences between browsers can affect results, so compare like-for-like when possible.
- Running on battery-saver mode - many laptops throttle CPU performance to save power.
Frequently Asked Questions
Why is my score different from Cinebench or Geekbench?
Browser JavaScript runs through an interpreted/JIT-compiled engine rather than native machine code, so raw numbers aren't directly comparable to dedicated native benchmarking tools, though relative comparisons still hold.
Does this test my GPU too?
No, this benchmark is CPU-only. For GPU information, use the dedicated GPU Tester.
Why does my score vary between runs?
Background processes, browser tab activity, and thermal conditions can all cause small variations between runs - try running it a few times and comparing your best result.
Conclusion
This benchmark gives you a quick, no-install way to gauge your CPU's single-core performance. Pair it with the GPU Tester and Network Latency Test for a fuller picture of your system.