Prime95 vs stress-ng

Prime95 is free Mersenne-prime search software for people who want to contribute computing work to GIMPS. It can also put a sustained workload across CPU cores to check processor and L1, L2, and L3 cache stability. For project tasks, Prime95 contacts PrimeNet for work; users can monitor computer progress and manage assignments remotely through the account’s CPUs page. Listed work includes PRP and Lucas-Lehmer tests, P-1 and ECM factoring, and trial factoring. Downloads include Windows, Linux, Mac OS X command-line, and FreeBSD builds. Administrators can choose a GUI-less Windows service build, which is intended for Windows Server experts. The source archive covers Windows, Linux, FreeBSD, and Mac OS X, though the code is described as non-portable. Version 30.3 introduced a dialog for limiting resource use. GIMPS participation is free and open internationally. The license permits indefinite free use on computers users own or are authorized to use, and provides the software as-is without warranty.

stress-ng is a free utility for loading computer subsystems and operating system kernel interfaces with stress tests. Its project lists more than 390 tests, including suites for CPU, virtual memory, filesystems, and memory or CPU caches. CPU tests exercise floating-point, integer, bit-manipulation, and control-flow operations. Listed architecture coverage includes ARM, x86-64, RISC-V, MIPS, Power, SPARC, and s390x. The project originally aimed to reveal hardware problems such as thermal overruns and operating system bugs under heavy load. stress-ng can report test throughput to help observe performance changes between operating system releases or hardware types, but the project says it is not a precise benchmark suite. Some tests may heat poorly designed hardware or create excessive system thrashing that is hard to stop. On Linux, running as root adjusts out-of-memory settings so stressors can become unkillable in low-memory conditions; the README advises careful use. The project documents Docker snapshots and installation on recent Ubuntu releases through its PPA. It is licensed under GPL-2.0 and costs nothing.