- Huge improvements to stage 2 of P-1 when lots of memory is available.
- Warning: upgrading in the middle of P-1 stage 2 will restart P-1 stage 2 from scratch
Joining GIMPS is usually as simple as downloading and running the program, answering a few questions, and the program does the rest.
There are cash awards for discovering a new Mersenne prime!
If you have not done so, create your UserID. It's optional, but required to check your account details, computer status and performance statistics and to assign computers to your user ID.
Download the appropriate free program for your OS (see below for GPU software) and proceed to Step 3:
|Operating System||Version||Released||Size||Download||Notes / Checksums|
|Mac OS X||30.8b15||2022-07-28||4.7MB||p95v308b15.MacOSX.tar.gz|
|FreeBSD 11+: 64-bit||30.7b9||2021-11-15||7.1MB||p95v307b9.FreeBSD11-64.tar.gz|
|Windows Service: 64-bit||30.8b15||2022-05-06||8.3MB||p95v308b15.win64.service.zip|
|Windows Service: 32-bit||30.8b15||2022-05-06||7.1MB||p95v308b15.win32.service.zip|
|Legacy Operating Systems|
|Mac OS X, GUI version||29.8b7||2020-03-19||5.0MB||p95v298b7.MacOSX.tar.gz|
|Mac OS X|
|FreeBSD 10: 64-bit||28.7||2015-08-10||5.3MB||p95v287.FreeBSD10-64.tar.gz|
|FreeBSD 8: 64-bit||27.9||2012-12-12||4.5MB||p95v279.FreeBSD64.tar.gz|
|FreeBSD 7: 32-bit||26.6||2011-04-08||4.0MB||mprime266-FreeBSD.tar.gz|
|Windows XP: 32-bit||29.8b6||2019-08-18||5.4MB||p95v298b6.win32.zip|
Create a directory and decompress the file you just downloaded. Windows 10, 8, 7, Vista, and XP have built-in unzip features. Other Windows users can choose from a variety of decompression programs. We use 7-zip. Linux and FreeBSD users should use the standard tar and gzip decompression utilities.
Start the program! Linux and FreeBSD users should run the program from the command line with a -m switch, i.e. ./mprime -m
Enter your optional userID created on the website in Step 1, and optionally name your computer. We recommend Windows users select Options » Start at Bootup or Start at Logon.
That's all you need to do! The program contacts a central server called PrimeNet to get some work to do. Usually the program and PrimeNet know the best work to assign, but it's up to you! You can administer your account and computers on your userID's account page. Once you complete a workunit you can track your standings on the competitive stats pages the server updates every hour (see Top Producers in the menu, left, for more stats). You can monitor each of your computers' progress, even remote-control the work assignments they request using your userID's CPUs page!
Linux and FreeBSD versions can also be set up to run every time you restart your computer.
Ask for help at the Mersenne Forum.
Prime95 has been a popular choice for stress / torture testing a CPU since its introduction, especially with overclockers and system builders. Since the software makes heavy use of the processor's integer and floating point instructions, it feeds the processor a consistent and verifiable workload to test the stability of the CPU and the L1/L2/L3 processor cache. Additionally, it uses all of the cores of a multi-CPU / multi-core system to ensure a high-load stress test environment.
From the most recent "stress.txt" file included in the download:
The Prime95 Wikipedia page has an excellent overview on using Prime95 to test your system and ensure it is working properly. The tips presented there should be helpful regarding how long to run the torture test and provide a solid guideline on how long to run the Prime95 stress test.
Performing a stress test is simple:
Download the appropriate program for your OS
Upgrade the software. Stop and exit your current version, then install the new version overwriting the previous version. You can upgrade even if you are in the middle of testing an exponent.
Restart the program.
Please consult the readme.txt file for possible answers. You can also search for an answer, or ask for help in the GIMPS forums. Otherwise, you will need to address your question to one of the two people who wrote the program. Networking and server problems should be sent to GIMPS admin. Such problems include errors contacting the server, problems with assignments or userids, and errors on the server's statistics page. All other problems and questions should be sent to George Woltman, but please consult the forums first.
See GIMPS Terms and Conditions. However, please do send bug reports and suggestions for improvements.
If you use GIMPS source code to find Mersenne primes, you must agree to adhere to the GIMPS free software license agreement. Other than that restriction, you may use this code as you see fit.
The source code for the program is highly optimized Intel assembly language. There are many more-readable FFT algorithms available on the web and in textbooks. The program is also completely non-portable. If you are curious anyway, you can download all the source code (49.0MB). This file includes all the version 30.8b15 source code for Windows, Linux, FreeBSD, and Mac OS X. Last updated: 2022-05-06.
The GIMPS program is very loosely based on C code written by Richard Crandall. Luke Welsh has started a web page that points to Richard Crandall's program and other available source code that you can use to help search for Mersenne primes.
At this time, Ernst Mayer's Mlucas program is the best choice for non-Intel architectures. Luke Welsh has a web page that points to available source code of mostly historical interest you can use to help search for Mersenne primes.