Download Prime95 - a handy tool for overclockers and system stability checkers, Prime95 has a feature called "Torture Test" that allows maximum stress testing on the CPU and RAM. There are several options allowing the stress test to focus on the memory, processor, or a balance of both.

Usually Prime95 will detect an error within a matter of minutes if an overclock is not stable, however many people like to let the system "burn-in" overnight to ensure long-term stability. FPrime95 is a small and easy to use application that allows you to find Mersenne Prime numbers. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test.

Prime numbers have long fascinated amateur and professional mathematicians. An integer greater than one is called a prime number if its only divisors are one and itself. The first prime numbers are 2, 3, 5, 7, 11, etc. For example, the number 10 is not prime because it is divisible by 2 and 5. A Mersenne prime is a prime of the form 2P-1. The first Mersenne primes are 3, 7, 31, 127, etc. There are only 40 known Mersenne primes. 

There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. Recommended for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working.

New features

• PRP proofs. This allows GIMPS to double-check a PRP test at less than 1% of the cost of a full PRP test!
• PRP proofs require lots of temporary disk space. See readme.txt for details.
• PRP proofs require uploading a large proof file. See readme.txt for details.
• PRP proof verifications require downloading a modest verification file. See readme.txt for details.
• Proofs automatically uploaded to server in 30.2.
• First time LL, World-record LL, 100M-digit LL work preference is deprecated.
• New resource limits menu choice and dialog box. Consult readme.txt before making changes to these settings.
• Some options previously in Test/Worker Windows and Options/CPU are moved to the resources dialog box.
• LL-DC and PRP-DC combined into a single work preference.
• Warning raised if temporary disk space is less than 1.5GB -- you may not get first time prime tests.

The benefit of this version is that it is multi-threaded and will automatically manage worker threads to fully stress all cores of your CPU.

Change Info:
New features in Version 30.7 of prime95.exe ------------------------------------------- 1) Better prime pairing in stage 2 of ECM/P-1/P+1. This usually results in slightly better stage 2 timings or less memory used. Save file formats changed - upgrading to 30.7 while ECM/P-1/P+1 work is in stage 2 will result in stage 2 being restarted from scratch. 2) P-1 converted to use P+1 style stage 2. From the users perpective there is no difference. Internally a modular inverse is required at stage 2 init, but there is one multiplication saved for every D-block processed. For all common P-1 cases, this is a little faster. 3) ECM/P-1/P+1 no longer use a bit map for prime pairs. Instead a compressed pairing map is created to save memory. For large B2 values this also results in fewer calls to generate pairing maps. It also makes stage 2 save files smaller. 4) Some minor changes in AVX-512 FFT crossovers. ECM/P-1/P+1 all changed to rollback to the last save file and switch to a larger FFT size should an excessive roundoff error be encountered. 5) Support for asymmetric processor architectures such as Intel's Alder Lake. 6) Torture test dialog now asks for number of cores to test along with a "Use hyperthreading" checkbox. Previously, the dialog box asked for total number of torture threads to execute. 7) Versions 30.4/30.5/30.6 were underestimating the cost of P-1 stage 2 relative to P-1 stage 1. Expect this version to use lower stage 2 bounds in P-1.