Stress Testing A Computer Using HeavyLoad

Stress testing a computer can be a good way to diagnose intermittent hardware problems that cause software errors or computer crashes. It is also used to prove that the hardware in a new or upgraded computer is up to the job. We take a look at HeavyLoad – a useful free utility for stress testing.

If you are seeing intermittent crashes (blue screens), freezing or unexpected shutdowns when using your computer, it can be difficult to determine whether the cause is software or hardware related. Stress testing means putting key components of computer hardware under stress i.e. a constant full load (usage) to test whether the computer freezes or crashes – it shouldn’t!

For example, testing a processor at 100% load for a few hours helps determine that it will function ok in all normal use (when it will likely only be running at 10 – 50% load). Computer shops assembling (or upgrading) a computer may stress test it for 12 hours or more to ensure there are no hardware problems.

We will use the free HeavyLoad utility to stress test.

  • First, it is important to use temperature monitoring software when stress testing so you can keep an eye on temperatures – if you don’t have any, follow our guide on using Speccy to monitor temperatures
  • Open your temperature monitoring software and position it on screen so that you can see it as well as the HeavyLoad program (to keep an eye on temps)
  • Download HeavyLoad from here – we recommend choosing the portable zip file version ( so you don’t have to install it
  • Unzip the downloaded file into a folder named HeavyLoad and run the HeavyLoad.exe program file to open the program as shown in the example below:


  • Initially the program just tracks your current CPU usage, Free Hard Disk Space and Free Memory in the chart
  • The stress testing options are straightforward – at the top left of the window there are 6 important buttons (clicking on a button turns it on/off):

Start button – starts stress testing
Stop button – stops stress testing
CPU button – enabled by default, tests the CPU (processor) at full 100% load
Hard Drive button – writes a continuous file to a temp folder on your hard drive
Memory button – allocates (uses up) physical and virtual memory in a continuous cycle
Tree Size button – opens one instance of TreeSize Free for each partition on your hard drive(s) so can be used to see where your hard drive space has gone – see our review of TreeSize Free

  • Choose your options – we advise running each of the 3 tests (CPU/Hard Disk/Memory) one at a time to pin down any problems to a particular component. If none of the 3 individual tests cause any problems then we would enable all 3 of them and then run a final combined test for full coverage
  • Click the Start button to commence stress testing and the Stop button when you have finished. Running for a few minutes is unlikely to prove anything – unless you have a major temperature issue. Running for at least a few hours is more likely to prove whether hardware faults exist but do watch out for overheating temperatures (especially on laptops) and stop the test if temps are going through the roof to prevent damage to components

Warning – Stress testing, by definition, can cause a computer with hardware faults to misbehave/crash or shut down as it pushes components to their limits.

This can help in diagnosing an intermittent problem but it could cause premature or even total failure of a component e.g. if a hard drive is on its last legs, stress testing could just finish it off (it would likely have failed soon anyway but such a risk increases with stress testing).

Unless you are stress testing a brand new computer, it is always wise to make sure that you have a good up to date backup of all important data before stress testing.