• Intel Alder Lake support. Improvements to stage 2 of P-1, ECM. Added P+1 factoring.
• Warning: upgrading in the middle of P-1 stage 2 will restart P-1 stage 2 from scratch

Setup Instructions for New Users

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!

1. 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.

2. 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
   Windows: 64-bit	30.7b9	2021-11-15	9.9MB	p95v307b9.win64.zip	MD5:    174f03c7505a77d639600bfc6df79617 SHA1:   0bd23035fce5ddfefdb196dc2eb64cea8290cf4d SHA256: 119480c2910cd4fe6aee6b408bc24a063b33f444d92cfefd70af5d85f58a645d
   Windows: 32-bit	30.7b9	2021-11-15	8.4MB	p95v307b9.win32.zip	MD5:    986e31da9b991a35efe30b19c3370704 SHA1:   c15fd836f85d8779015b4aa1b8d6a0ad9d3f1f34 SHA256: 6747bca84d089b803aebe3428a2506a613177dd106de5e9415135ffcb601433a
   Linux: 64-bit	30.7b9	2021-11-15	6.8MB	p95v307b9.linux64.tar.gz	MD5:    053e3f8afdb8275345cfbe94207612da SHA1:   f57bcc5c5d7403a4a7ee0d32abab01d8da114ed8 SHA256: d47d766c734d1cca4521cf7b37c1fe351c2cf1fbe5b7c70c457061a897a5a380
   Linux: 32-bit	30.7b9	2021-11-15	5.7MB	p95v307b9.linux32.tar.gz	MD5:    6537e79e3495e9cf0921f81e28ef9f52 SHA1:   d5ab3a1cc1ae2c320f64295a22ec2b44ba290be2 SHA256: 3ff40a24632c56d5bcf15c0ebc41a34cd025c0c9a3dc1c6550db92b21c1e806f
   Mac OS X	29.8b7	2020-03-19	5.0MB	p95v298b7.MacOSX.tar.gz	Requires Intel CPU, Mac OS X 10.9 (Mavericks) or later MD5:    5a110a0a5210fd10d7b8da0ce9ff43cf SHA1:   5a93d5f45dadd09b60520176f9abaead7c22d356 SHA256: 3a0e228ea35bd96824163c7f5ab8e21502a33ae647752de3e5aab0f88fc7c52e
   Mac OS X command line version	29.8b7	2020-03-19	4.5MB	p95v298b7.MacOSX.noGUI.tar.gz	No GUI. Requires Intel CPU, Mac OS X 10.7 or later. MD5:    9b6920d933d3c70eadd5a0942088881c SHA1:   7a20a100697c2c545db2f45c7973378d46875ccb SHA256: d0b4e447f67249dd5483dc1afc883e535c69632787eb70e9f42e9c15fed04a26
   FreeBSD 11+: 64-bit	30.7b9	2021-11-15	7.1MB	p95v307b9.FreeBSD11-64.tar.gz	Requires FreeBSD 11.0 MD5:    a88718f5d985c3a0e0f76323969ffcaf SHA1:   767e890fb914e5a81b0ee6c0df9b4624408caf4a SHA256: 750a36bce52d33db7c6765ea454d12a25aea0b967b99642d3847cb87c7e844a5
   Windows Service: 64-bit	30.7b9	2021-11-15	8.2MB	p95v307b9.win64.service.zip	This is for administrators that want the extra security of running a traditional GUI-less service. You will still need to download the standard windows executable to configure the client. This program is for Windows Server experts only. MD5:    ac51f8e7d6825ff7062ab8fd8375b09f SHA1:   83601ceaa36ba8bc409bbe74d37c0de161db32ea SHA256: d1cfdaaaf2094ace93672dbb77aa2d5409849d812cdb64fef8d05bf5ebdaa6de
   Windows Service: 32-bit	30.7b9	2021-11-15	7.0MB	p95v307b9.win32.service.zip	This is for administrators that want the extra security of running a traditional GUI-less service. You will still need to download the standard windows executable to configure the client. This program is for Windows Server experts only. MD5:    abc3d048c91f588264420dd4de5c464d SHA1:   9dd735fd6b9a0074408fcdfd95bda14a2be35769 SHA256: 6e50ca83cbe15a8f13688fee8b6b2c12c754ffefc7d7c068af3e76908534a4a1
   Source code	30.7b9	2021-11-15	48.6MB	p95v307b9.source.zip	for Windows, Linux, FreeBSD, and Mac OS X MD5:    407b2883f2e10d05ce5c127402cc4d10 SHA1:   37542b66fb2d3fdb8903ab07602a8009b0cb628d SHA256: e89ce78b01eb3055f5503eabd9d0aec95e1e832361f3f2987098969fe649fdb5
   GPU Software If you have a recent discrete videocard powered by an AMD or NVIDIA GPU, it's potentially more powerful than your CPU at prime-testing (or factoring) Mersenne numbers. Visit the Mersenne GPU Computing Forum for more information. Some Mersenne-related software has been written for NVIDIA and AMD GPUs, including: primality test (PRP): gpuowl trial-factoring (TF): mfaktc (NVIDIA) / mfakto (AMD)
   Legacy Operating Systems
   Mac OS X pre-Mavericks	27.9	2012-12-12	5.1MB	p95v279.MacOSX.zip	Requires Mac OS X 10.3 to 10.8 and an Intel CPU. MD5:    0390ae2ff3d4a7082927482d82e62f59 SHA1:   5f08298fb4aff5dbbab3d072519cd80ecce576c1 SHA256: c44e3bdae50d3360ec58a0efff47ccfdff5bdc5d31f669e2761da4737d5560d8
   FreeBSD 10: 64-bit	28.7	2015-08-10	5.3MB	p95v287.FreeBSD10-64.tar.gz	Requires FreeBSD 10.0 MD5:    5dd21b471946fdcb4858a9fa50fe718b SHA1:   5143e7e355f8fdbce5b3629cc9cd8d4e9bd04592 SHA256: 0a04bb01524e7c10edce501f57e902b3ce9f82cda0e39aaae8bfaa1af95ab416
   FreeBSD 8: 64-bit	27.9	2012-12-12	4.5MB	p95v279.FreeBSD64.tar.gz	Requires FreeBSD 8.0. May work on later versions. MD5:    c6b1c84a79bb1b2e8366a81ddea0087c SHA1:   0f2972edb728a017b3bfe7da5cb7fddad7ed785c SHA256: 5ab9feddeb53fca9d9684119fae7ac271de3d85a4dd3c3f1fd26ab97ff71c05a
   FreeBSD 7: 32-bit	26.6	2011-04-08	4.0MB	mprime266-FreeBSD.tar.gz	Requires FreeBSD 7.0. May work on later versions. MD5:    d7e78a458b0c7ebbd6db57ff08835739 SHA1:   b283278dea4887494ebb7357992981ece8df3e08 SHA256: d4c2c044cfa45311dd7f2c41574f59a0519c989fd6e0ca723505dea12b2ff1fd
   Windows XP: 32-bit	29.8b6	2019-08-18	5.4MB	p95v298b6.win32.zip	MD5:    4f7d1cc7904d5d9ccb26c8c00b6470a9 SHA1:   54dd8f9b4692d7a878626ac993562b83cb5587fb SHA256: cdd32b4c358869d3f588ae430bc67d9e88a5a69506002f864adac3c477c9202a
   non-x86 OS	Unix and non-x86 users should check out Ernst Mayer's Mlucas page .

3. 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.

4. 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.

CPU Stress / Torture Testing

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:

1. Download the software and unzip the files to your desired location.
2. Run the Prime95 executable and select "Just Stress Testing" when asked.
3. The default options are sufficient to do a well balanced stress test on the system.

Upgrade Instructions for Existing Users

1. Download the appropriate program for your OS

2. 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.

3. Restart the program.

4. Read WhatsNew.txt

Questions and Problems

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.

Disclaimers

See GIMPS Terms and Conditions. However, please do send bug reports and suggestions for improvements.

Software Source Code

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 (48.6MB). This file includes all the version 30.7b9 source code for Windows, Linux, FreeBSD, and Mac OS X. Last updated: 2021-11-15.

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.

Other available freeware

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.