Updated 21 October 202610 min readReleases and platforms Prime95 has been around for decades, and the version you run affects which instruction sets it uses, which operating systems it supports and how hard it hits your CPU. This page summarises the version history from the official download page, explains what changed between the versions that … Read more

Updated 21 October 202611 min readAMD Ryzen tuning Curve Optimizer lets Ryzen owners lower the voltage the CPU requests at each frequency, which can mean lower temperatures or higher boost clocks. The catch is stability: a setting that sails through an all-core Prime95 run can still crash at idle or in light loads. This guide … Read more

Updated 21 October 202612 min readTool comparison Prime95, OCCT, AIDA64 and Cinebench all get lumped together as “CPU tests”, but they do very different jobs. Two are stress tests, one is a wider stability suite that also tests memory and graphics, and one is mainly a benchmark. Choosing the right one depends on whether you … Read more

Updated 21 October 202611 min readInstruction sets and local.txt Prime95 can use AVX, AVX2 and, on supported CPUs, AVX-512 instructions. These wide instructions do more work per clock, and they usually draw more power and produce more heat than ordinary code. Knowing what they do, and how to switch them off, lets you choose between … Read more

Updated 21 October 202612 min readTroubleshooting A Prime95 error isn’t the test being broken. It’s the test doing its job: it found a calculation that came out wrong, and it stopped that worker to tell you. This guide explains the common messages, what usually causes them, and a step-by-step order for fixing them without guessing. … Read more

Updated 21 October 202611 min readDownload safety and hardware safety “Is Prime95 safe?” is really two different questions. Is the file safe to download and run, and is running it safe for your hardware? The answers are different, and both come down to where you get the program and how you run it. This guide … Read more

Updated 21 October 202612 min readIntel and AMD Prime95 will push a CPU to temperatures that games and everyday apps never reach, so the first question most people ask is how hot is too hot. The honest answer depends on your exact processor, your cooler and what the CPU does at its limit. This guide … Read more

Updated 21 October 202613 min readPrime95 torture test modes The three main tests in Prime95’s torture test window don’t measure the same thing. A CPU can pass hours of Small FFTs and still crash under Blend or Large FFTs, because each mode loads a different part of your system. This guide explains what an FFT … Read more

Updated 21 October 202614 min readWindows, Prime95 30.19 build 20 Prime95 is one of the most demanding CPU stress tests ever written, which is exactly why overclockers, system builders and repair shops still use it. This guide shows you how to run a Prime95 stress test on Windows from start to finish: what to prepare, … Read more