PrimeNet Parallel Test Challenge
Updated 1/3/98

Current Internet PrimeNet Server Test Status (updated hourly)

Upgrading Prime95 14.4/PrimeNet 2.6 Parallel Test Challenge Clients to Prime95 15.4

Now with Prime95 15.4!

No fuss, 'start and forget' parallel research - try our parallel test challenge! It is the client half of PrimeNet 3.0, packaged with Prime95.exe 15.4, ready to install and run.

Put your office or home PC to work! The Prime95 test program runs only in your computer's idle CPU cycles. No jerky mouse cursor, no 'sticky' typing, no slow applications. Period. Aside from a tiny pink icon in the task bar near the clock, you will never notice it's even there. (But you can check on it any time!)

This is for anyone who wants to partiticipate in the Great Internet Mersenne Prime Search project, but wouldn't miss the work of getting monthly assignment ranges, e-mailing the test results, etc. You install the software and start it up - thereafter it needs only to have you connect to the Internet a few minutes a month!

Any Windows 95/98 or NT computer with Internet access, dial-up or not, can participate! All test assignments originate from, and all test results benefit, the Great Internet Mersenne Prime Search project. All test work is credited to your account.

Free WinNT 4.0/Win95 software to download:
[unzip it into a directory folder you create, and open readme.txt, inside]

PrimeNet Freeware License Agreement: Primenet software is licensed for free use if you do not sell it, sell parts of it, or include it as part of a sold product or use it for a sold service. No warranties or liabilities are assumed, offered or implied. Use of Primenet software constitutes implicit agreement with the terms of this freeware license.

For details, please refer to the readme.txt file packaged with Prime95 15.4, or see Woltman's GIMPS project web site.

To get the most processing time out of your computer:

Upgrading Prime95 14.4 / PrimeNet 2.6 Parallel Test Challenge Clients

Note: These instructions only apply to PrimeNet 2.6 test clients using Prime95 14.4 with the Internet PrimeNet Server.

Prime95 15.4 is equipped to retain your existing account. All work performed by Prime95 15.4 is credited by both the Internet PrimeNet Server Parallel Test Challenge and George Woltman.

To upgrade Prime95 to version 15.4 in place, please use this procedure:

  1. Stop Prime95 14.4. Go to the IPS status page at and get an online report of your account assignments. Have this on hand for step 6.

  2. Copy all files in your current Prime95 test folder into another folder for safety.

  3. Unzip the downloaded file in your test folder, and overwrite Prime95.exe and primenet.dll with the new 15.4 versions.

  4. If you have a primenet.spl file and want the Internet PrimeNet Server to credit this work, e-mail your results or results.txt file to

  5. Delete primenet.bin and primenet.spl, if you have these files. You can optionally e-mail these files to me before you delete them so guarantee the server is up to date. Keep any pXXXXXX or qXXXXXX files from your interrupted Lucas-Lehmer test. Keep your results or results.txt file, too.

    Unlike Prime95 14.4, Prime95 15.4 will first factor all your assigned exponents first, and then resume work on the interrupted Lucas-Lehmer assignment.

  6. Use Notepad to create a file called worktodo.ini in your test folder. For each Lucas-Lehmer exponent assigned to your account on the report from step 1., enter a line (for example, exponent 9876543 factored through 58 bits):


    Similarly, for factoring exponents:


    Save this file, and exit.

  7. Start Prime95, and when prompted for your information, set your existing account user ID and password (only the first 8 characters) in the user information dialog.

  8. Your results or results.txt file will be transmitted to the server under your account ID. If you had a primenet.spl file, some results may not get credited by IPS, but will be credited by Woltman.

  9. That's it! Periodically check your account status using the Internet PrimeNet Server status page web form.