Prime95 has been around since the dawn of time and used by overclockers to stability test CPU overclocks by place a heavy load on the CPU as well as the rest of the computer hardware. This maximises heat output and voltage drain.
Back in the day, unlocked multipliers were reserved for the elite. As a result, we needed software capable of simultaneously putting a huge amount of stress on both the processer and ram because there was a lot of front-side bus overclocking.
Today, overclocking has evolved; most processors have unlocked multipliers, and if they don’t, there is always an accessible modal.
Regardless of the state of overclocking, Prime95 remains one of the best overclocking tools in our arsenal here at PerformancePSU to really burn our components and test the stability of our big overclocks.
If you are not a small talk type of person, you can skip straight to the best prime95 settings section.
What is Prime95?
Primarily a CPU stress testing tool or CPU stability test as it’s sometimes also called. Prime95 places an extreme amount of pressure on your entire computer system, including your power supply, memory, processor and motherboard, using a set of predefined tests.
Prime95 works by requesting that your computer’s hardware calculate prime numbers in rapid succession and will do this until;
- It finds a unique prime number at which point you will be notified by a sound.
- You stop the test (our ideal scenario)
- Your hardware fails and the test fails due to a miscalculation (our worst case scenario)
What are the best Prime95 Settings?
For most people, setting your Prime95 torture test to blend is the perfect way to tell if your computers overclock quickly is stable or not but, what if you want to push your pc components further and really put them through a real stability test? The burning type of CPU stability test that would even make the devil go weak at the knees?
Say hello to custom Prime95 settings designed to maximise the load on your entire system. If your overclocking PC can complete 24 hours at these settings, nothing will bring your overclock to its knees – ever.
How to setup Prime95 with Custom Settings
- You will need to download Prime95 if you don’t already have it.
- Start a New Torture Test
- Select Custom Blend
- Set the number of threads to the number of cores you have (double that for virtual cores)
- Press Ctrl + Alt + Delete to check the available ram in start task manager under the Performance tab
- Calculate 90% of your total system memory using the following calculation:
amount_of_memory_in_mb * .9
- In the box that reads “Memory to use in MB” insert the sum of step 3
- Click Start
Note: Once you start the custom test, you will notice your entire system slows down with these Prime95 settings. So don’t expect to be casually browsing Reddit or playing some games while the custom stability test is running.
Commonly Asked Questions (2)
How long should I run Prime95 for?
PerformancePSU advises to run Prime95 for 12 – 24 hours to make sure your system is 100% stable. Normally though, unstable overclocks will show up pretty fast, normally within around the 30-60 minute mark which is where it can be handy to run a simple blend test.
Does Prime95 test my Graphics Card (GPU)?
Prime95 stability tests your processor, ram, power supply and motherboard. It cannot stability test your graphics cards (GPU) because it does not have the available instructions to make use of them.