Free Online Fossil CPU Load or Stress Test. Simulates CPU Partial or Full Load.

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  Load Duty Cycle

0% 25%    50% 75% 100%

Just click on the controls above to start loading the CPU.

0% is no load. 100% is full load (infinite loop).

Actual load on system depends on


Use to load CPU:

Usage Notes

Use Fossil PC Speed to check PC speed reduction caused by this utility. Note Fossil PC Speed before and after running CPU Load Test.

For accurate results, run Fossil PC Speed in a separate process. Use ps or task manager, to display running processes, to confirm. To make sure of this, use a different web browser software (e.g. Firefox for PC Speed, Opera for CPU Load).

CPU Load Test cannot seize more CPU resources than allocated by the OS to the web browser. To increase the CPU load:

Can be used to simulate application behaviour on older, slower machines

Use at your own risk

These online tools are meant to be used by IT professionals and power users. People who

  • know what they are doing and who understand the limitations of web-based software
  • recognize the possibility of bugs in software, the complexity of the interactions between applications, CPUs (including multi-core), RAM, operating system (task scheduler, memory manager etc). And therefore carefully interpret and check the results reported by any software.


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