Checking RAM for Hardware Errors

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One of the more common reasons a PC may refuse to start or experience issues can be tied to one of the most utilized components in the system:  RAM.  RAM issues can manifest in many different ways such as:

  • Applications/Games freezing, hanging, or crashing
  • Random PC restarts
  • Stop Code/Stop Screen, aka BSOD (Blue Screen of Death)
  • No Signal to the Monitor
  • Not Booting into Windows

If you are looking for information on how to identify a potential RAM issue, please check our guide found here:

NZXT Support - Identifying RAM Issues

If you have identified a RAM issue with your PC and the PC is able to complete POST (Power on Self Test) with a signal to the monitor, this guide will help in confirming the issue.

RAM Testing Software

When confirming a RAM issue with your PC, there are various tools available that can help us with testing the RAM based both within and outside of Windows itself.  For this guide, we’ll primarily be using the Windows Memory Diagnostic tool as well as OCCT and MemTest86.

When choosing the program to use, you’ll want to confirm if you can first load into Windows itself:

I can load into Windows I cannot load into Windows
Windows Memory Diagnostic Windows Memory Diagnostic
OCCT MemTest86


Using Windows Memory Diagnostic

There are two primary ways to load the Windows Memory Diagnostic depending on if you are able to load into Windows or not.  If you are having difficulty booting into Windows because of a Blue Screen or freeze during startup, you may need to create a Windows Installation USB in order to run the test.  You can find our more about creating a Windows Installation USB from the guides listed below:

Loading inside Windows

To load the Windows Memory Diagnostic from within Windows, open your Start Menu and in the Search bar use the term Windows Memory Diagnostic to pull up the program.  If you have hidden your Search bar, you can still type to search for this program.


Run the Windows Memory Diagnostic program and you will be prompted to either Restart now and check for problems (recommended) or Check for problems the next time I start my computer.  For this test, we will be going with the Restart now option.

If you are having difficulties loading from the Start menu, you can press Win+R on your keyboard to open the Run box and type mdsched to open the program instead.


Once the PC restarts, it will load into the Windows Memory Diagnostic tool and run automatically.  Once the test completes, the PC will restart and any errors found will be reported in the Event Viewer within Windows.  To pull this up, search for Event Viewer in the Start Menu and in the program make sure to choose Windows Logs followed by System and look for an Information item with the MemoryDiagnostics-Results source.


Loading the Windows Recovery Environment (WinRE)

If you are not able to load into Windows properly, you may instead need to load the Windows Memory Diagnostic from the Windows Recovery Environment (WinRE).  This can be done either from a Windows Installation disk or from your system’s own Recovery partition.

If you are not able to load directly into Windows properly, you may instead need to load the Windows Memory Diagnostic program from the Windows Recovery Environment, otherwise known as WinRE.  There are three ways we can load WinRE for the memory diagnostic:

  • Method 1:  Enter WinRE from the Motherboard Splash screen
  • Method 2:  Enter WinRE by interrupting Windows startup
  • Method 3:  Enter WinRE by using a Windows Install USB

Method 1: Entering WinRE from the Motherboard Splash screen


When starting your PC, you'll be presented with a Motherboard splash screen as shown above.  This screen will usually show the name of your motherboard, as well as instructions to enter various options such as the Boot Menu, BIOS Setup, etc.  On this screen, rapidly press the F8 key until you see a white circle indicating that Windows has begun loading.  If done correctly, Windows will load immediately into WinRE instead of the operating system.

If you miss the timing, the system will simply load into Windows as normal so you'll need to shutdown the PC and try again or use one of the other methods.

Method 2:  Entering WinRE by interrupting Windows startup

Before starting this method, make sure your PC is completely shutdown and identify the Power Supply On/Off switch on the rear of your PC.  A power switch will be necessary for this method to properly interrupt the system.  Please do not attempt this using the power button on top of the PC, as it may not be fast enough to properly interrupt the boot process.


When starting your PC, you'll be presented with a Motherboard splash screen, followed by the Windows boot screen.  On most PCs, this will be represented either by the same splash screen with a white loading circle or a screen with the Microsoft Windows logo and a white loading circle.

Once the loading circle appears, turn off the PC using the power switch located on the rear of the PC to interrupt the startup.  Repeat this process an additional 2 times and on the 4th boot allow the PC to boot normally.  If done successfully, you'll receive a message stating that Windows is Preparing Automatic Repair.  Once completed, you'll be brought to a blue Automatic Repair screen with options to either Restart or Shutdown your PC as well as an Advanced options button.  Please select Advanced options to open WinRE.

Method 3:  Entering WinRE by using a Windows Install USB

To load into WinRE from a Windows Installation disk, restart your PC and press either Delete to enter the UEFI/BIOS or if you are given a prompt to enter the Boot Menu press the appropriate key. 


For most NZXT motherboards, the F11 button will bring up the Boot Menu during launch.

In the BIOS, you may have a Boot Override or Boot Menu option on the main page or in the Save & Exit section.  Select the flash drive in the appropriate menu and the PC should boot directly into the Windows Installer.

With the Installer loaded, select your language if prompted then on the next screen choose Repair your Computer to load WinRE. 

Running Windows Memory Diagnostic in WinRE

Once you are loaded into WinRE, select Troubleshoot followed by Advanced options and finally Command Prompt.  Depending on how your system is configured, you may need to select your Windows account and log in with your password after selecting Command Prompt.


Within the Command Prompt, type in the command mdsched and press enter to launch the Windows Memory Diagnostic tool and choose Restart now and check for problems (recommended).

As you may not be able to load back into Windows with a memory error, it is recommended to take a picture of the screen once a memory error is detected.

Using MemTest86

Considered by many to be the go-to tool for RAM testing, MemTest86 is a powerful tool that can be used without needing to boot into Windows directly.  For situations where a Stop Code prevents you from getting into Windows, MemTest86 is a great option to run before jumping to reinstalling the operating system as a whole.

To get started, you’ll need the following:

  • A USB Flash Drive
  • A working PC running Windows

Note:  Creating a bootable flash drive using this guide will result in a total loss of all data on the target flash drive, please make sure to either backup any important files on the drive or use a fresh flash drive.

Download the MemTest86 program from the following link, for this guide you will be using the Free version:

PassMark Software - MemTest86 Download

Extract the contents of the .zip file downloaded to a folder on your desktop, then insert the target flash drive and run the imageUSB program included in the folder.  Select your flash drive from the list of available drives, then choose Write image to USB drive.  If there is no image file selected, click the Browse button and select the .img file in the folder we extracted earlier in the guide.  From here, simply click Write and follow the prompts given by the program.  Once completed, your drive will be ready for use.


With the PC turned off, insert the flash drive and start the PC.  When you see the BIOS splash screen, press either Delete on the keyboard to enter the BIOS or if a Boot Menu option is available use that shortcut instead.  From the BIOS’s Boot Override or the Boot Menu, select the flash drive to boot from and the test will run automatically after a few seconds.


For more information, please refer to the User Guide document included with the MemTest86 download.

Using OCCT

Another tool that can be used to test for memory issues within Windows is OCCT, which includes a number of tests that can be used to check for errors and stability issues on your PC.

This program can be downloaded for free from the official site here and is the one of the tests we use in house for validating systems following assembly or repair.


Make sure that the Memory test is selected, then click the Start button at the bottom of the test window to begin the test.  If OCCT detects any memory errors, these will be logged on the program itself.

My test confirmed an error, what do I do now?

Once a RAM error is confirmed in a testing program, you’ll want to isolate the issue.  If your system only has a single match pair of RAM modules, try repeating the test with a single module installed at a time.  If your system has two or more match pairs, try testing each pair separately before testing individual modules.

For more information on reseating your RAM for this isolation testing, please refer to the Identifying RAM Issues guide linked at the top of the page.

If you have confirmed a RAM issue with an NZXT BLD PC, please reach out to our Customer Support team for further assistance.

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