Prime95 is a software primarily used for performing the Lucas-Lehmer primality test for Mersenne numbers. You can type in any prime number in the Prime95 test and it will perform numerous iterations to find out if that prime number is also a Mersenne number. A Mersenne number in mathematics is a prime number that is one less than two raised to power of another number. Well, that all is very interesting for mathematical geniuses, but for the rest of us Prime95 can also stress test the computer hardware that can be useful in finding out if the overclocking configuration of your hardware is working well.
As you launch the Prime95 software, it gives you options to join GIMPS or just perform the stress test. GIMPS is an online network for calculating huge prime numbers using the Prime95 software and shared processing power of all the people using it worldwide. For hardware stress testing purposes, you can just click on the Just Stress Testing button and proceed.
This will open the options window from where you can choose the type of test that you want to perform – small FFT, large FFT, blend or custom. The blend test is selected by default and is also recommended for complete stress testing of the CPU as well as the physical memory (RAM).
As the test begins a progress is displayed in the text format. It shows the number of Lucas-Lehmer iteration being performed for testing a Mersenne number for each step of the test. if your hardware is not properly configured, then the test may encounter an error during the primality test of a number. Otherwise, it displays no errors or warnings for the tests being performed.
Prime95 is a simple hardware stress tester that limits itself to the CPU and RAM related testing. Other features provided by a modern computer, like GPU, DirectX, OpenGL etc., are totally ignored by it. If you are looking for a complete stress tester, then perhaps you would like to read about Catzilla or Heavyload.
You can download Prime95 from http://www.mersenne.org/download/.