Use Windows Memory Diagnostic to Test RAM — Historical Guide

Windows Memory Diagnostic is a built-in memory test that can help identify defective RAM. The interface described here comes from Windows 7-era systems, but the mdsched tool continues to exist in current Windows.

Run the test from Windows

1. Open Start and search for Windows Memory Diagnostic, or press Windows key + R and run:

mdsched

2. Choose Restart now and check for problems or schedule the test for the next restart.
3. The PC restarts and the memory test runs before Windows loads.

Use the advanced test options

While Windows Memory Diagnostic is running, press F1. Depending on the Windows version, you can choose:

• Basic, Standard, or Extended test mix.
• Cache behavior.
• Number of passes.

Press F10 to apply the selected options and continue testing.

If Windows will not start

On Windows 7-era recovery media, memory diagnostics may also be available from the recovery/boot tools. The exact F-key boot menu varies by PC and should not be assumed to be identical on every machine.

Interpreting the result

A reported memory error is significant and should be followed up with hardware diagnostics or replacement testing. A clean pass does not guarantee that intermittent RAM, motherboard, or memory-controller faults are impossible.

Official reference

• Microsoft: Windows Memory Diagnostic workflow: https://support.microsoft.com/en-us/windows/experience/performance-optimization/how-to-fix-error-0xa-irql-not-less-or-equal