Possibly faulty RAM

Introduction

Quite often, the presence of random unexplained problems is caused by faulty RAM. This is easy to test and is a good first step to diagnose.

Windows - Quick test

1. If you have a few spare hours when you don’t need your computer, please run Extended test instead.

2. The test will take around half an hour. You won’t be able to use your computer while the test runs. It could be convenient to run it during the lunch break.

3. Run from Win+R or from command line:

   MdSched.exe
   

4. Choose whether to restart now or postpone it until next restart.

5. Once your computer is restarted, the test will run automatically.

6. If you need your computer before the test completes, you can interrupt it with Esc and run again later.

7. Once the test is finished, the computer will automatically boot back into Windows.

8. You can find test results in Windows Event Log :
   a. Go to Control Panel > System and Security > Administrative Tools > Event Viewer > Windows Logs > System

   b. Find event with Source equal to MemoryDiagnostics-Results

9. If the test detected any errors, read this chapter.

10. Sometimes, a quick test does not detect errors. Please also run Extended test.

Windows - Extended test

1. The test will take a few hours. You won’t be able to use your computer while the test runs. It could be convenient to run during the night.

2. Run from Win+R or from command line:

   MdSched.exe
   

3. Choose whether to restart now or postpone it until next restart.

4. Once your computer is restarted, the test will run automatically.

5. Press F1 and select Extended test mix. Press F10 to apply.

6. If you need your computer before the test completes, you can interrupt it with Esc and run again later.

7. Once the test is finished, the computer will automatically boot back into Windows.

8. You can find test results in Windows Event Log :
   a. Go to Control Panel > System and Security > Administrative Tools > Event Viewer > Windows Logs > System

   b. Find event with Source equal to MemoryDiagnostics-Results

9. If the test detected any errors, read this chapter.

Test detected errors?

1. Even if just a single error was detected, your RAM is faulty and it’s best to replace it.
2. Having a test error means that a specific location in memory changes its values unpredictably. The more locations are faulty, the higher the probability of unexpected errors.
3. Depending on which program gets this memory you can observe crashes, blue screens, all other forms of unexpected behavior. Or it can work “fine”, if non-important data was corrupted this time, such as a single pixel in some image on screen.
4. On every computer restart, the error will likely corrupt something new, so random programs will crash.
5. If you have multiple RAM chips, you can find the faulty one by removing them one by one and running the test again.