Software Windows

My computer keeps crashing. How do I test the RAM on a PC?

black and gray computer motherboard
Testing times: make sure your memory is working properly (Photo by Valentine Tanasovich on

There are countless glitches that can bring a computer to its knees, but faulty RAM is always near the top of the list of likely contenders. Despite established production runs and top-notch manufacturing techniques, it’s not uncommon for RAM modules to develop a fault, making your machine unpredictable and unreliable. Here’s how to test the RAM on a PC.

We’ll cover two different methods, one super simple, the other a little more involved, but much more thorough.

Method 1: Test the RAM on a PC using Windows Memory Diagnostics

Those lovely people at Microsoft have built a memory diagnostic tool into Windows. Although there are a few ways to access it, we’ll show you the easiest method.  This method works for both Windows 10 and Windows 11.

Microsoft Windows Run box containing mdsched.exe command

Open the Start menu and type RUN into the search box and select the Run app from the menu. Alternatively, press Windows key and R. In the Run box, type mdsched.exe

Windows Memory Diagnostic screenshot.

The Windows Memory Diagnostic box appears, choose whichever option you fancy. Both will take you to the same place.

Windows Memory Diagnostic Tool launch screenshot

During the next restart, the Windows Memory Diagnostic Tool will launch and don’t be fooled by its retro looks, which is dated compared to modern apps. Memory testing is a serious business, but not necessarily an exciting one. The test will begin automatically and, depending on how much RAM is in your system, may take some time. The test will run with defaults, but you can change these by pressing F1.

Windows Memory Diagnostic Tool options launch screenshot

The options screen gives access to three versions of the test: Basic, Standard and Extended. Pressing the TAB key steps you through each option, showing which testing options are covered. You can also press TAB to change the cycle count. This is the number of times that the tests are run. Running RAM tests multiple times is an excellent idea, so we advise you to up the cycle count. Understandably, altering these options could extend the time that it takes for the test to run.

Once the test is complete, the machine will reboot.

Method 2: Test the RAM on a PC using MemTest86

Although a RAM test can be performed from within Windows, a more comprehensive tool is MemTest86. It’s a free app which will run directly from a USB stick. Passmark, the makers of MemTest86, has created a lovely step-by-step tutorial video of how to download, install and run the software. You’ll require a USB stick (8GB or above) and Rufus (another free download) which will create a bootable USB for you.

MemTest launch screenshot

Once your machine has booted from the USB, MemTest86 will take a few moments to load. When the screen above appears, select Config.

MemTest options screenshot

MemTest86 can perform some extremely specific tests based on your requirements. It can select specific memory address ranges as well as perform RAM benchmarking. As we’re only here for testing, we’ll concentrate on that. Select T, to enter the Test Selection menu.

MemTest test selection screenshot

In its default mode, MemTest86 will auto-select the best options for general RAM tests. The Test Selection screen will allow you to increase the number of passes and I would advise that you do this. The free version of MemTest86 will allow up to four passes, so if you want more, you’ll need to pay them a few quid.

MemTest Pass screenshot

Windows Memory Diagnostic is perfectly adequate for testing the RAM on a PC, but some of its options are limited. Another downside is that Windows needs to be operational for it to run, so if your machine is crashing during the boot cycle, then skip our first method and use the second.

It’s not a bad idea to test the RAM on a PC from time to time, but it’s imperative to do it after a RAM upgrade. A simple test could prevent hours of troubleshooting.

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About the author

Lee Grant

I can normally be found attacking things with screwdrivers in my small computer repair business or writing a column for PC Pro magazine.

I am also trying to solve a mystery involving David Bowie.

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