- Diagnose RAM with mdsched.exe and view events 1101 and 1201 in the Viewer.
- Extend your analysis with MemTest, MemTest86, and AIDA64 to detect elusive errors.
- Isolate the problem by modules and slots and adjust BIOS if there is instability.
When your computer starts to cause problems with random crashes, blue screens, or unexplained slowness, one of the most common suspicions is the RAM. Check memory with the Windows mdsched.exe tool It is a quick and reliable first step to rule out failures that affect system stability.
In the following lines you will find a complete guide, from start to finish, to detect symptoms, run the native Microsoft test, read the results in the Event Viewer and, if you need it, Move on to more comprehensive tests with third-party utilities such as MemTest, MemTest86, or AIDA64You'll also see what to do when errors appear and how to identify the problematic module without going crazy.
When to suspect that RAM is failing
Before measuring and diagnosing, it is important to recognize the signs. Many RAM problems manifest as system crashes that could confuse you with disk errors or errors from the disk itself. Windows.
- Beeps when starting: Some equipment emits acoustic codes (or relies on LEDs on the board) that indicate errors in hardware.
- Eternal starts, even with SSD NVMe, and performance that declines the longer you have the PC on.
- BSOD or blue screens When opening programs or games, codes like MEMORY_MANAGEMENT often point to memory.
- Files that open corrupted or inaccessible: the read may be failing in RAM, not the disk.
- Less RAM recognized in Settings > About Windows (for example, you have 16 GB and you see 8 GB).
Be careful, not all symptoms imply a broken module. Lack of memory also causes crashes and errors if the system runs short on resources, especially on computers with 8 GB or less and heavy loads.
Before any software testing, it is worth doing two basic checks. Reseat the RAM modules and change slots to rule out poor contact or a bad motherboard socket, and also check RAM consumption in real time.
How to use Windows Memory Diagnostic (mdsched.exe)
Windows 10 and 11 include a native checker called Windows Memory Diagnostic. It runs before the system loads, so you can analyze RAM with minimal process interference.
Open the tool in any of these ways: Press Windows + R, type mdsched.exe and confirm, or search for Windows Memory Diagnostic from the Start menu. You can also find it under Windows Tools in the list of system utilities.
A window will open with two options. The recommended one is Reboot now and check for any issues. If you can't stop what you're doing, choose to run the scan at the next Boot.
Upon reboot, you will see a blue test screen. Press F1 to open advanced options and choose the test type, cache management and number of repetitions.
Analysis modes and advanced options
The tool offers three depth profiles, and it's good to know what each one does. The longer the test, the more comprehensive it is. will be the analysis and better ability to detect intermittent errors.
- Basic: Includes MATS+, INVC, and SCHCKR with caching enabled; it is the fastest for initial screening.
- Standard: adds LRAND, Stride6, CHCKR3, WMATS+, and WINVC; balance between time and intensity.
- Extended: incorporates Stride38, WSCHCKR, WStride6, CHCKR4, WCHCKR3, ERAND and CHCKR8, with the cache disabled; is the most thorough and can take hours.
In addition to the mode, you can set the cache to Default, On, or Off. Disabling the cache forces more direct memory accesses, useful for uncovering errors that the cache masks.
Finally, it is possible to define the number of passes. You can repeat the test battery up to 99 times.; if you enter 0, execution is indefinite until you manually cancel it.
On the main screen you will see progress, overall percentage, number of tests and errors detected in real time. When finished, the computer restarts itself and Windows loads as usual.
View the results in the Event Viewer
After the restart, a notification may appear informing you of the result, but it won't always give you all the details. The full report is in the Event Viewer, within the system logs.
To open it, press Windows + R, type eventvwr.msc and accept, or search for Event Viewer from the Start menu. In the left panel, go to Windows Logs and choose System.
In the right pane, use the Filter Current Record option. In Event Sources type MemoryDiagnostics-Results and apply the filter to see only relevant entries.
You are especially interested in events with ID 1101 and 1201, which summarize the result of the last diagnostic run. Double-click the event to see if errors were detected and, if so, how many and at what stage.
If the display shows no problems but suspicions persist, don't stop there. Some intermittent failures require longer and more aggressive testing. that Microsoft's verifier doesn't cover in as much depth; Check out our guide to diagnosing hardware failures.
If the display shows no problems but suspicions persist, don't stop there. Some intermittent failures require longer and more aggressive testing. that Microsoft's verifier doesn't cover in as much depth.
Advanced testing with third-party utilities
When you need to go a step further, you have several options. MemTest, MemTest86 and AIDA64 These are three popular tools for stressing memory with different patterns and methodologies; There are also specific guides for memory testing on macOS. if you work at Apple.
MemTest for Windows
MemTest is a classic in Windows environment. The basic version is free and sufficient to detect obvious errors; the Pro edition adds features for a very reasonable price (approximately $5).
Its use is simple: you run the application, indicate the amount of RAM to test and launch the test. It is ideal for spending several hours checking while you work with the computer normally, although it is best to close heavy programs.
MemTest86 bootable from USB
MemTest86 is a de facto standard for off-OS testing. It runs from a USB or boot CD, with multiple passes and patterns that uncover elusive flaws.
Versions and licenses: there are free and paid editionsIn the commercial range, you'll find advanced versions with licenses that can reach high prices for professional use, while the free version covers the needs of most home users.
Basic steps to use it: download the image from its official website, create the USB with a tool like Rufus, boot the PC from that media and let it run your full battery of tests. Weather execution will vary depending on the amount and speed of RAM.
If MemTest86 finds errors, note them. Repeated failures in the same directions or patterns They usually point to faulty modules or overly aggressive memory parameters in BIOS.
AIDA64 and its memory test
AIDA64 is a very complete diagnostic and benchmarking suite. Includes memory and cache tests which, although performance-oriented, can help uncover instabilities under sustained load.
To run your test, install the app, go to the Benchmark section, and run the memory tests. In addition to checking stability, you will get read, write and latency rates. to compare whether your team is performing as it should.
Practical tips to limit the problem
When there are errors, don't rush into buying. Locate the faulty module and check compatibility before replacing.
- Test module by module: Turn off the equipment, leave a single stick, alternate slots and repeat the tests.
- Check the BIOS: Disable XMP/EXPO profiles and return to JEDEC settings to see if the errors disappear. You can also adjust memory for the iGPU.
- Update BIOS/UEFI: New versions improve compatibility and fix IMC (memory controller).
- Verify that Windows recognizes all memory: If GB is missing, it could be a module, socket, or firmware limitation.
If everything points to RAM, assess the age of your platform. Finding compatible modules on older equipment can be difficult., and sometimes it is worth upgrading the motherboard, CPU and RAM.
When RAM is insufficient for your tasks (editing, VM, modern games), it is not a hardware failure, but a limitation. Increasing capacity can eliminate crashes and BSODs due to lack of resources., improving the experience without any further mystery.
Errors detected: what to do next
If diagnostics, either with mdsched.exe or third-party tools, confirm problems, there are several paths. The most direct way is to replace the affected module. for another compatible with your motherboard.
Before purchasing, check the warranty. If the modules are under warranty, process RMA with the manufacturer, attaching screenshots or reports from MemTest86 or other evidence as proof.
If you decide to rush, you can try to fine-tune timings and frequencies downwards. Adjusting clocks and latencies can stabilize memories that are too tight, but it is an advanced process and does not always solve a physical defect.
Also check the physical location of the modules. It only takes one tab not to fit properly. to cause intermittent errors. Clean contacts carefully if necessary.
In scenarios with isolated errors that appear after hours of use, prioritize extended testing. Runs mdsched.exe extended mode and several passes of MemTest86 to increase the probability of detection.
Errors that are not the fault of RAM
Finally, don't lose sight of other components. An unstable CPU overclock, a poor power supply, or a motherboard with a VRM at its limit can cause similar symptoms.
Update drivers, check temperatures, and pass CPU and GPU stress tests. Discarding the rest of the system avoids false positives and gives you a more solid diagnosis.
On disks, read errors or corrupt files they can deceive. If the SSD SMARTs show problems, perhaps the bottleneck is not in the RAM but in the storage.
You now have a complete procedure: recognize signals, test with mdsched.exe, read reports in the Event Viewer, reinforce with MemTest86 or AIDA64 if doubts persist, and act accordingly. Once confirmed that the RAM is fine, you can focus on other causes without wasting time or money.
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