Download Prime95 29.2

The distributed computing project Gimps, which stands for Great Internet Mersenne Prime Search, searches for Mersenne primes. Those are primes that are exactly one less than a power of two, or 2n – 1. The first four n numbers to form the first four Mersenne primes are 2, 3, 5 and 7, where 3, 7, 31 and 127 comes out. The required program is called Prime95 and is listed under a own license released. Version 29.2 is recent appeared for FreeBSD, Linux (32, 64bit), macOS and Windows (32, 64bit), of course you can also source the source code. The list of improvements looks like this:

New features in Version 29.2 or prime95.exe

• Throughput benchmarks of all FFT implementations are written to gwnum.txt. These benchmarks will then be used to pick the best FFT implementation to use. This can lead to minor performance improvements.
• Benchmarks are run at 5AM (and every 21 hours after that) for any FFT sizes that will be needed within the next 7 days. Once enough benchmark data is accumulated, these automatic benchmarks no longer take place.
• Default FFT implementations for Ryzen added.
• A few new FFT sizes (up to 50M) are enabled for FMA3-capable CPUs.
• ECM and P-1 on Fermat numbers will automatically add known Fermat factors to the worktodo.txt entries.

Bug fixes

• The Windows version does not use new benchmark data in FFT selection until prime95 is restarted. Fixed in 29.2 build 3.
• Throughput benchmarks using less than all cores improperly used all cores. Fixed in 29.2 build 4.
• Using benchmark data on AMD Bulldozer with SUM(INPUTS) checking enabled can lead to errors initializing FFTs. Fixed in 29.2 build 5.
• Auto benchmark runs even if user is not running any workers. Auto benchmark runs on battery power even if “run on battery power” option is not selected. Fixed in 29.2 build 5.