How to Run Windows Memory Diagnostic

What Windows Memory Diagnostic does

Windows Memory Diagnostic is a utility included with Windows 11 and earlier versions that checks your system RAM for hardware errors. RAM errors can cause crashes, freezes, blue screens, and corrupted data during gameplay. The tool writes patterns to each memory module and reads them back to find inconsistencies.

The diagnostic runs outside of Windows, before the operating system loads, so it can access all memory without interference. It does not require any additional software or installation. This makes it a reliable first step when you suspect memory issues.

For a gaming PC, stable RAM is essential. The minimum system requirement for Windows 11 is 4GB of RAM, but gaming systems typically use 16GB or 32GB. Learning to run this diagnostic helps you confirm that your memory is functioning correctly, which is part of choosing a gaming PC.

Why memory errors affect gaming performance

A gaming PC relies on RAM to hold the data that the CPU and GPU need while you play. If a memory module fails intermittently, you might see random application crashes, screen freezes, or blue screens that are hard to reproduce. The diagnostic can reveal whether the problem lies in the RAM itself.

High-resolution displays and large game worlds increase the amount of data stored in RAM, so a single faulty module can become obvious under load. The diagnostic is a simple way to rule out memory before you look at other components.

Understanding RAM capacity and speed also helps. For detailed guidance on how much RAM your gaming style needs, see how much RAM do you need for gaming.

How to launch the diagnostic

There are two simple ways to start Windows Memory Diagnostic. The quickest method is to open the Run dialog by pressing the Windows key and R at the same time, then type mdsched.exe and press Enter. A window appears asking when you want to run the check.

Alternatively, you can open the Control Panel, select Administrative Tools, and double-click Windows Memory Diagnostic. The same prompt appears.

Choose "Restart now and check for problems" to run the diagnostic immediately, or "Check for problems the next time I start my computer" if you need to save work first. The system restarts and the diagnostic begins automatically. If you are using a prebuilt gaming PC, this tool is part of the standard Windows environment, alongside other options like Windows Game Mode.

What happens during the memory check

After restarting, the screen shows a blue background with a progress bar. The tool runs a standard check by default, which includes a series of read-write patterns across all RAM modules. This pass usually takes a few minutes depending on the amount of memory installed.

You can press the F1 key during the scan to open options. Here you can select an extended check that runs more patterns and takes longer, or a basic check that runs fewer patterns. The extended mode is more thorough but can take hours on systems with 32GB or more of RAM.

The tool runs two passes by default. You can change the number of passes in the F1 menu. When the scan finishes, the PC restarts automatically and boots into Windows. This process is independent of your storage drive, so it works even if you are using an NVMe SSD.

How to read the results

After Windows loads, a notification may appear in the system tray saying whether errors were found. If you miss that notification, you can find the full report in Event Viewer.

To open Event Viewer, press Windows+X and select Event Viewer. Navigate to Windows Logs and then System. Look for events with the source "MemoryDiagnostics-Results" or "Wininit". The event ID is 1101 for a completed diagnostic. The message will state "No errors" or list the number of errors found.

If errors are reported, the RAM module or slot may be faulty. The diagnostic does not identify which specific stick has the problem, so you may need to remove modules one at a time and rerun the check to isolate the issue. This troubleshooting step is similar to checking other hardware components, as described in what to check in a prebuilt gaming PC.

When to run the diagnostic on your gaming PC

Run Windows Memory Diagnostic if your gaming PC experiences random crashes, blue screens with memory-related error codes, or applications that close unexpectedly. It is also a good idea to run it after installing new RAM modules to confirm they are working correctly.

If you are building a new gaming PC or upgrading memory, running the diagnostic after the first boot helps catch faulty modules early. The tool is also useful when troubleshooting intermittent issues that other diagnostics do not find.

For a gaming PC that runs smoothly, running the diagnostic once a year or after any hardware change is a reasonable maintenance step. If you are looking for a new system with verified memory, check the best prebuilt gaming PCs or best RAM for gaming.

What to pick for your play

Questions

Does Windows Memory Diagnostic delete my data?

No, the diagnostic only reads and writes patterns to RAM. It does not access your storage drives or modify any files.

How long does the extended check take?

The extended check runs more patterns and can take several hours on a system with 32GB of RAM. The standard check usually finishes in a few minutes.

Can I use my PC while the diagnostic is running?

No, the diagnostic runs before Windows loads. You cannot use the PC until the scan completes and the system restarts.

What should I do if errors are found?

If errors appear, the RAM module or motherboard slot may be faulty. Try reseating the modules, then run the diagnostic again. If errors persist, replace the affected module.

Is Windows Memory Diagnostic available on Windows 10?

Yes, the tool is included in Windows 10 and Windows 11. The steps to launch it are the same on both versions.

Do I need to run the diagnostic on a new gaming PC?

It is a good practice to run the diagnostic after receiving a new prebuilt gaming PC or after installing new RAM to confirm the memory is stable.