About this test
A free PC stress test that runs in your browser
SystemCheck loads your processor, memory and graphics hardware for a fixed length of time and records what they deliver the whole way through, not just the best moment. Most benchmarks report a peak, which is the number a machine can hold for a few seconds. The number that decides whether a laptop is pleasant to work on is the one it still holds in the third minute, and that is the number this test is built to find.
There is nothing to install and no account to make. The run happens in this tab, and the report opens in plain words before any of the technical sections.
What the stress test measures
- Sustained CPU load
- Every logical core is loaded for a full minute and throughput is recorded in 250 ms windows, so the result is what the processor delivered rather than what it reached once. The shape of that curve is what tells you whether the machine held its speed, stepped down when a power budget expired, or slid steadily as cooling fell behind.
- Memory bandwidth and latency
- Read and write bandwidth from one thread and from all threads at once, and the round-trip time to cache and to main memory. A machine can have a fast processor and still feel slow if it is waiting on memory, and the two are measured separately here so you can tell which.
- Calibrated GPU raster load
- A fixed scene is scaled to your graphics hardware and then held there, so frame time, frame pacing and decay are comparable between runs on the same machine. Pacing matters more than the average: a steady 45 frames per second looks better than an average of 60 delivered unevenly.
- Path tracing
- A sample-gated path tracer runs for a fixed time and reports samples per second and how consistently they were delivered. It is the heaviest thing a browser can ask of a GPU and the stage where a thermally limited laptop usually separates from a desktop.
A deep run adds three more stages: your display’s refresh rate and frame pacing, a combined load with the processor and graphics working at once, and a repeat of the CPU stage on the already-warmed machine, which is the clearest single test of whether cooling is the limit. The methodology page sets out each stage in full.
What it cannot measure
A browser is a restricted place to measure from, and pretending otherwise is how benchmarks end up quoting numbers they never read. These are the limits:
- Temperatures in degrees. A browser has no sensor access, so decay is measured as lost throughput and the cause is inferred from its shape, never reported as a reading.
- Fan speed, voltages and power draw in watts. None are exposed to a web page on any browser.
- Your exact processor and graphics model, unless you name the processor yourself. The browser reports a rendering string, not a part number.
- Anything about other machines. Every figure is measured on the device in front of you, in this tab, during this run.
Questions people ask before running it
Is this PC stress test free?
Yes. The test itself and every measured number in the report are free, with no account and no install. A one-time payment unlocks the diagnosis section, which names the likely cause of a slowdown and what to change about it. Nothing that was measured is placed behind that payment.
How long does the stress test take?
A standard run takes exactly 3 minutes across four stages. A deep run takes 8 minutes across seven, adding your display's refresh and frame pacing, a combined CPU and GPU load, and a hot re-test of the processor on the already-warmed machine.
Can a browser stress test really load my CPU properly?
It can saturate every logical core through Web Workers, which is enough to make a thermal or power limit show itself, and that is what this test is looking for. It will not reach the absolute peak throughput of a native tool, so treat the absolute numbers as a floor and the shape of the curve over time as the real result.
Is it safe to stress test my PC?
A modern processor and graphics card protect themselves by slowing down long before they can be damaged, and that slowdown is exactly what this test measures. The run is short and stops the moment you close the tab. If your machine is already unstable or its cooling is obstructed, expect it to throttle or crash sooner under any load, including this one.
Do I need to install anything or make an account?
No. The test runs entirely in this tab. Nothing is uploaded and nothing is stored on our side unless you ask for a copy of the report by email.
Why did my score change between two runs?
Usually because the machine was warmer, on battery, or busy with something else. Run-to-run spread is reported as its own figure rather than hidden, and a deep run takes the median of three CPU passes so a single unlucky run does not decide the result.