PC stress test: how to check your computer's stability and performance
A stress test fully loads the processor, memory and graphics card for hours and shows whether the computer runs stably and does not overheat. A benchmark then measures performance and lets you compare it with other builds. Both are worth doing after building a new PC, after an upgrade, or when the computer restarts on its own.
Summary
- A stress test looks for errors and overheating; a benchmark measures performance.
- Test the processor, memory and graphics separately, then everything together.
- Monitor temperatures, clocks and voltages during the tests.
- The final test is several hours of real gaming.
Why test your computer
Some faults do not show up straight away. Memory may produce errors only under full load, the power supply may cut out only during a graphics card power spike, and a badly mounted cooler only makes itself known after a few minutes of gaming. A combination of components that are each fine on their own can also behave unstably together. A stress test brings these problems out before you lose a game in progress or unsaved work.
That is why the computers we build at PC Praha go through a stress test of the processor, graphics and memory, with temperature checks, before handover.
What to test with
| Program | What it tests | What it is for |
|---|---|---|
| AIDA64 | processor, memory, drives, the whole system | stability stress test, sensor monitoring (temperatures, voltages, fan speeds) |
| OCCT | processor, memory, graphics, power supply | stress tests with error detection, power supply test under full load |
| MemTest86 | system memory | thorough RAM test outside Windows (from USB) |
| FurMark | graphics card | maximum GPU load, checking the card's cooling |
| 3DMark | graphics and processor | gaming benchmarks (e.g. Time Spy, Steel Nomad) and stability stress tests |
| Unigine Superposition | graphics card | benchmark and cooling system load |
| Cinebench | processor | single-core and all-core performance when rendering a 3D scene |
| PCMark 10 | the whole computer | performance in everyday office and multimedia tasks |
How to run the test step by step
- Prepare: update the BIOS and drivers, close other programs and start sensor monitoring (for example in AIDA64 or HWiNFO).
- Processor: run a CPU stress test for 30–60 minutes. Watch the temperature and whether the processor lowers its clocks due to overheating (throttling).
- Memory: run a memory test – ideally several passes of MemTest86. A single error means a problem with the module or the settings (often the XMP/EXPO profile).
- Graphics: 20–30 minutes of FurMark or the 3DMark stress test. Watch the temperature, clocks and any artefacts on screen.
- Everything at once: run CPU and GPU load at the same time. This also tests the power supply and the airflow in the case.
- Benchmark: measure performance in 3DMark and Cinebench and compare it with online results for the same components.
- Real gaming: several hours in a demanding game at high detail is the best final test.
How to read the results
- The test crashed, the computer restarted or reports an error: an unstable component, memory settings or a weak power supply.
- High temperatures and dropping clocks: insufficient cooling, dried-out thermal paste or poor airflow in the case. Maximum safe temperatures vary by model – you will find them from the processor and graphics card manufacturer.
- Artefacts on screen (coloured dots, squares): often a problem with the graphics card's memory.
- Low benchmark score: check that the memory runs in dual-channel mode with the correct profile and that the graphics card is in the fastest PCIe slot.
FurMark and similar tests load a graphics card more than any game. On older or overheating cards, run them only briefly and keep an eye on temperatures.
What next
- Computer repair and service – diagnosing random restarts, blue screens and overheating.
- Custom PC builds – we test the computer before handover.
- How to choose a PC power supply – the most common cause of instability.
Frequently asked questions
How long should a stress test last?
Can a stress test damage my computer?
Why does my computer restart during a test?
What is the difference between a benchmark and a stress test?
This text was prepared with the help of AI. Facts, figures and procedures were checked by Yegor.