No. 21 of 30 ·PC Overclocking Software

Prime95

Windows · Mac · Linux · Self-hosted

Freedom report

Two barsScore 5.2

Free tierA free tier is on its own pricing page
Open codeNo open-source code on record
Runs widely3 of 6 device platforms
DocumentedThinly documented

Prime95 is ranked #21 of 30 in PC overclocking software on Freedom251. It runs on Linux, macOS, Self-hosted, Windows. There is a free plan.

Prime95 plans and pricing

All plans

Prime95 Free Free to download and use indefinitely on computers you own or are authorized to use · participation is free of charge mersenne.org · 7 Oct 2026

Compared on PC overclocking software

Free plan: Yes
Platform support: multi-platform
Stress testing: Yes

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The record

Purpose: Prime95 is free Mersenne prime search software used to participate in GIMPS.
PrimeNet coordination: The program contacts PrimeNet to receive work, and users can view computer progress and remotely control work assignments from the account CPUs page.
Supported downloads: The current download page lists Windows, Linux, Mac OS X command-line, and FreeBSD builds.
Windows service: A GUI-less Windows service build is available for administrators, and the page says it is for Windows Server experts only.
Source code: The source archive is listed for Windows, Linux, FreeBSD, and Mac OS X, and the page describes the code as highly optimized Intel assembly and completely non-portable.
Test types: The download page lists PRP tests, Lucas-Lehmer tests, P-1 and ECM factoring, and trial factoring among its project work and software features.
Resource controls: Version 30.3 introduced a Resource Limits dialog to control Prime95 resource usage.
Hardware support: The page says recent NVIDIA or AMD discrete GPUs may be more powerful than a CPU for prime testing or factoring, with separate GPU programs communicating with PrimeNet through AutoPrimeNet.
Participation: GIMPS participation is free of charge and open to the public internationally.
Privacy: GIMPS says it will not sell, distribute, or release participants’ email addresses or other supplied information except where required by law.
License and warranty: The EULA allows indefinite free use on computers owned by the user or where they have permission, and provides the software and information as is without warranty.
Support: The download page directs users to the Mersenne Forum for help and lists email contacts for networking/server issues and other software questions.
Maker: Mersenne Research, Inc. owns and operates Mersenne.org and is described as a California nonprofit organized for mathematical and computer science research and related education.
Founded: 1996
Price from: Free

Where it ranks on Freedom251

Best PC Overclocking Software in 2026#21 of 30
Best Hardware Diagnostic Software in 2026#14 of 25

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Sources

mersenne.org/download/· checked 7 Oct 2026
mersenne.org/legal/· checked 7 Oct 2026