CPU stress/load testing

From time to time it might be handy to ensure that your CPU is still able to cope with intense workloads. Only thing is, for most of us it's hard to give our CPUs a sustained workload with real world work... enter CPU stress testing!

One of the methods we use to test if a CPU is performing as expected is by installing HWiNFO and running it in sensors only mode, then starting up your CPU stress test of choice (detailed below) and running that.

The CPU clock speeds (seen in HWiNFO) should get to just about the max CPU boost speeds advertised on some of the cores - it will unlikely be a sustained number, but it should show you that in the Max column. The reason max boost cannot be sustained or perhaps even achieved by all cores is that it is not intended to operate like that from the very inception of the CPU. Max boost is made so that tasks that require a lot of processing but just for a short period of time can happen ASAP, and sustained loads can ping up to or near max (depending on how the load hits) and then come down in order to maintain a healthy temperature.

Prime95

Prime95 will go through a variety of tests which will load up the CPU and RAM and get the temperatures up there and the fans going. This is usually left to run for a minimum of one hour on all systems, although more for some, in order to gauge the CPU's performance and temperatures.

How to run Prime95

Extract the contents of the Windows: 64-bit zip file into a folder made just for prime - this can be on the desktop or within your downloads folder, but all the files need to be extracted - then run prime95.exe, click Just Stress Testing when prompted, and then without changing the default selected options, click the OK button to start the tests.

AIDA64

Also a part of our arsenal, we run AIDA64, which attempts to run the CPU & RAM at 100% sustained load in order to test stability for both and also track how much the CPU is thermally throttling. It's normal for a CPU to thermal throttle, but the percentage shouldn't be too high (if it is, your inadequate cooling means performance is being lost).

Just like Prime95, it will load up the CPU and RAM and get the temperatures up there and the fans going. This is usually left to run for a minimum of one hour on all systems, although more for some, in order to gauge the CPU's performance and temperatures.

Running AIDA64

Run the aida64extreme.exe file to begin installation, upon completion allow AIDA64 to launch. Click OK to dismiss the warning, then select the Tools dropdown menu and System Stability Test. When you're ready, click Start.

Interpreting results

Both Prime95 and AIDA654 are CPU torture tests of types, but some of the tests that it cycles through also hits heavily on RAM, so a crash or freeze isn't necessarily telling us definitively that the CPU is to blame, but it gets us a step closer to figuring it out at least. If you are running this on a fresh installation of Windows 10/11, at least it's unlikely to be another bit of software/Windows update or driver corruption contributing. If it's not a fresh install, the results may be tainted.