What Is a Stress Test?
A stress test, in essence, is the process of pushing your CPU to the raggedy edge of its performance. It’s about testing the limits, pushing the performance to the max, turning the dial up to eleven. Feel free to add more euphemisms here, but you get the idea.
It’s basically about finding out how good your CPU is by getting the CPU to work 100%.
Why Stress Test?
There are several reasons why someone would want to stress test their CPU.
For enthusiasts like me, it’s sometimes just because we want to. It’s curiosity, that’s all. And the reason is that CPUs, in the real world, are rarely pushed to their limits. Even during heavy-use (elaborate spreadsheets, multithreaded applications, and so on), a CPU is never on the edge. The latest gaming CPUs, for example, rarely reach 50% to 60% usage in daily situations.
However, this isn’t the reason why most people stress test.
Overclocking is the primary reason people choose to stress test their CPUs. If you’ve overclocked your CPU, you want to know that it’s stable. You want to know that you can throw anything at it and it won’t just pout and crash.
The best way to ensure this is by stress testing or torture testing a CPU.
And stress tests are even helpful before you reach the maximum overclock figure. If your CPU seems to be stable for long periods of time at the current overclock, maybe there’s potential to overclock more.
And if you’re overclocking, let’s face it, you want to know how much higher you can go.
And then finally, PC builders run stress tests all the time. If you’ve just finished a new build or have finished an upgrade and then you observe sub-par performance, stress tests can help you where the problem lies.
For example, you stress test your CPU and find out that it’s absolutely fine. This clears any CPU bottleneck doubts. You can move on to check and test other components in your PC.
So, there you have it — from curiosity to overclocker’s enthusiasm, there are many reasons why someone would stress test a CPU. Thankfully, the process these days is really pretty simple. So, you could easily test your CPU to find out what all the fuss is about.
Warning ⚠️
I referred to the stress test as a torture test earlier. There’s a reason it’s called torture test. Stress tests really do torture your processor to extract every last ounce of performance. So, this process, as you might imagine, can cause damage to your CPU.
In fact, stress tests, when done without correct precaution or method, can and will permanently damage your process. This is true for GPU stress testing as well.
It might seem obvious, but in such cases, the warranty is useless. So, if you’ve just tested a high-end Intel gaming processor and damaged it, that’s on you!
So, erring on the side of safety is a good route to take on this road.
Preventing a Burnt CPU Scenario
The warning above sounds ominous, but it’s important to understand that if you take a few preventive measures, you should be just fine.
So, there are a couple of crucial aspects you need to take care of. One, temperature and two, power. By far, these are the most important factors when it comes to testing. So, at any point in the test, you need to be able to access information related to these two aspects.
As far as temperatures are concerned, CPUs are simple. 80 degree Celcius calls for caution, 90 asks you to be ready to abort, if you reach 93-94, you shut everything down. It’s time to boost cooling.
CPU Stress Testing Tools
There are two tools that you’ll need for a stress test. First, systems monitoring software. This is basically a simple lightweight application that will monitor important hardware information like temperature, clock speed, power, and so on.
As mentioned earlier, you’ll need to keep an eye on some of these figures while you test away. This application will help you to do so. There are several popular, free ones on the market like MSI Afterburner, Core Temp, the popular HWMonitor and so on. You’ll find one easily.
The more important tool is the actual testing software itself. There’s one application that’s become the standard in the industry.
Prime95
Prime95 is by far, the most popular choice when it comes to CPU stress tests. It’s free to use and more importantly, it’s brilliant at testing CPUs.
While a lot of testing applications rely on simulating real-world scenarios like videos and what not to test a CPU, Prime95 goes all math on CPUs.
Prime95 tests a processor by asking it to find Mersenne prime numbers. Without boring you with the details of what Mersenne prime numbers are, I’ll just tell you that it involves a lot of arithmetic maths… with very large numbers.
In a way, Prime95 converts a CPU into a very powerful calculator and asks it to perform tough calculations. This pushes a CPU to its absolute limits. Temperature, stability — everything is tested.
In fact, the software is so powerful that now, there’s a new option called ‘Torture Test’ that goes a bit soft on the mathematics so that the stability can be tested for long enough. No matter how high your CPU is on the CPU hierarchy, Prime95 will stress it to 100%.
Stress Testing
Once you have your monitoring software and the testing application installed and ready to go, we can begin testing!
Step 1: Overclock
Overclock your CPU to the desired speed.
However, if you don’t want to overclock your CPU and just want to test its stability at stock speeds, skip this step. But, if you do want to overclock but you aren’t sure exactly how to go about it, we have comprehensive guides on CPU overclocking and also GPU overclocking.
Go through them once and get back to this.
Step 2: Close Everything Irrelevant
Stress tests are tough on CPUs. So, you don’t want to add more to its problems. Make sure that you close all applications apart from the testing application and monitoring software. If you’ve overclocked your CPU, you don’t need monitoring software. Keep your overclocking tool open.
It’s especially important to close all applications that might stress your CPU like large Excel files, video or photo editing software — anything that can stress your CPU.
Having these applications open can lead to several problems. The test results may be corrupt, you might crash your system early, or worst-case scenario, you might actually cause some permanent damage to your processor.
So, close all applications apart from your monitoring or overclocking tool and the actual testing application.
Step 3: Torture Test
Open Prime95. On the menu, select ‘Options’. You should see a dropdown menu. Select ‘Torture Test’.
A window with a few options will open. You’ll have three main options. Blend, Small FFT, and Large FFT.
‘Blend test’ tests both the RAM and the CPU. FFT tests are focussed on the CPU alone. Pick your poison, they’re all equally lethal.
Once you select an option and click on the test, the testing begins. The test can run for as long as you want it. You can click ‘Stop’ whenever you like.
If there’s a problem or if the CPU isn’t stable, Prime95 will stop and show that there’s an error and the testing has stopped. Now, it doesn’t say what the error is. It just stops.
During the process, keep an eye out for the temperature at all times. If it goes higher than the threshold temperature, halt everything. Increase your cooling and turn down the overclock. Start over.
Step 4: Deciding on a Time Frame
Once the test has begun, it’s just a matter of deciding how long you want to test it.
The duration of testing depends on what exactly you’re trying to achieve with the test. If you’re an overclocker, you might want to test the processor for a long duration to check how stable it is. Once you know how long your CPU lasts, you’ll know how stable it is.
Here are a few handy pointers:
1 – 2 Hours
If you’re testing a stock processor or if you’ve introduced some very mild overclock, an hour or two of testing should be just fine. Mild overclocks, more often than not, are pretty darn stable anyways. So, if your CPU has made it through without any faults, you’re done!
6 Hours
A 6-hour test is for moderate overclocks. Now, there’s no hard and fast rule that it should be exactly 6 hours. The time duration is an educated approximation.
If your CPU lasts for around 6 hours, chances are, it’s good to use in the real world for almost all scenarios.
24 Hours
Usually, enthusiasts are the only people who will subject a CPU to a stress test for 24 hours. It’s done by overclockers who practice extreme overclocking and want to extract every last Hertz of speed out of the processor.
At these clock speeds, CPUs are quite unstable. So, tests have to be longer to confirm a stable overclock.
If your processor does this, first off, congratulations! That’s pretty amazing. And second, your processor is cleared for everything. No holds barred. Go forth, live and prosper with that CPU!
A Few Boxes to Check
Irrespective of how long or short your test duration is, there are a few things that you should ensure so that you get the best possible results.
100% Usage of CPU
This is the whole point of the test. It’s to push the performance of your processor to the max. So, don’t stop your test until you actually hit 100% CPU usage.
You can check for this using your overclocking tool or the systems monitor software.
You Need Good Cooling
This is for overclockers only. If you’ve overclocked your CPU and are now conducting a test, know that your CPU is going to get very hot very fast. There’s more power flowing through the CPU and on top of that, you’re stressing it. It’s bound to get hot.
Chances are, even for moderate overclocking, you will need extra cooling. There are some great cooling solutions out there. Make sure you have adequate cooling.
If you ask your processor to work very hard at very hot temperatures, you are inviting permanent damage.
Research Is a Good Friend to Have
You cannot push an Intel Core i3 8100 to 5 GHz. It’s just not possible. Before you go into beast mode with your overclocking, go online and see what sort of figures people are achieving. You may get 100-200 MHz more, but that’s about it.
You will not get a drastically different result. Persisting after a point will only ruin your hardware.
This is especially crucial when you’re stress testing your CPU. You are pushing the processor to its limit. Pushing too far will end badly… always.
Crashing Is Good
Now, that might seem wrong, but it really isn’t. Caution is important, yes. But, the entire point of a stress test is to find out when your CPU will give up. The point of failure is what you’re really after. So, go for it.
A crash might sound like it’s really bad, but it isn’t. In any case, have a backup. But even if you don’t, a crash isn’t a huge problem. PCs these days will shut down at amazing speeds and they do this well before any lasting damage is done to your system.
So, crashing isn’t bad at all. In fact, in stress tests, it’s good!
Conclusion
Irrespective of why you’re stress testing, the fact is that it exposes the point of failure of a processor and thus tells you how stable and reliable your CPU really is.
If you’re reasonably careful and proceed with caution, there’s really no reason to worry about hardware damage or failure.
So, go ahead and stress tests your first CPU. Let us know how it went!