Back up important files: faulty memory can corrupt data that is being saved. Write down your RAM kit model (on the module label or in its order) and the motherboard model. If Windows cannot start, see the startup guide.
Work through these checks
0 of 7 complete01Write down what the test reported
The number of errors, which test found them and whether they repeat decide which of the next steps matters most.
- In MemTest86, note the test number that failed, the number of errors and whether they appeared in every pass. Save the report if the program offers it.
- For Windows Memory Diagnostic, open Event Viewer (Win + R, eventvwr.msc), go to Windows Logs > System and look for the newest event from MemoryDiagnostics-Results.
- Note your current memory speed in the BIOS or in Task Manager > Performance > Memory.
You know whether errors are many or few, constant or occasional, and in which test.
If it does not helpThousands of errors at consecutive addresses in MemTest86 can be a sign it misread the memory size; a small number of failing bits is almost always a real error.
02Retest at default memory settings
XMP and EXPO profiles are factory overclocks. Many systems cannot run them reliably, especially with four modules or high-capacity kits, and the test then reports errors although the RAM is fine.
- Restart, enter the BIOS (usually Del or F2) and turn off XMP, EXPO or DOCP, or choose Load Optimized Defaults.
- Save and run the memory test again, at least four passes in MemTest86.
Do not raise memory or processor voltages to make errors go away unless you know the safe limits for your hardware.
The errors disappear at default speed.
If it does not helpIf they disappear, the RAM is probably fine but the profile is unstable. Use the default speed, or a lower speed than the profile, and test again. If errors remain at defaults, continue.
03Test each module on its own
Testing one module at a time shows whether a single module is faulty or whether the modules only fail together.
- Shut down, unplug the PC and leave only one module installed, in the slot the motherboard manual recommends for a single module.
- Run the test, then repeat with each of the other modules in the same slot.
- If every module passes alone, test them together again at default settings.
Touch a metal part of the case before handling RAM, and hold modules by their edges.
Either one module fails on its own, or all pass alone and fail only together.
If it does not helpOne failing module: it is faulty, go to the last step. Failing only together: the modules may be incompatible (for example different kits) or the memory controller cannot handle the full load; use a single matched kit or fewer modules.
04Reseat the modules and check the slots
A module that is not fully latched, or dust in a slot, causes intermittent errors that look like a faulty module.
- With the PC unplugged, remove each module and check the gold contacts and slots for dust or damage.
- Blow dust out of the slots with compressed air.
- Push each module in firmly until both latches click.
- If a module passes in one slot but fails in another, test a known-good module in the suspicious slot.
Errors that came from a poor connection go away.
If it does not helpIf the same slot fails with different modules, the slot or motherboard is at fault; contact the motherboard or PC manufacturer.
05Update the BIOS and check compatibility
BIOS updates often improve memory compatibility, and motherboard makers publish lists of tested memory kits.
- Find your motherboard model in System Information (Win + R, msinfo32, BaseBoard Product).
- On the manufacturer's support page, install the latest BIOS following their instructions.
- Check whether your RAM kit is on the board's memory support list (QVL) and whether the manual mentions limits for four modules.
Do not switch off the PC during a BIOS update.
The board runs the newest memory support code, and you know whether the kit is a tested combination.
If it does not helpRun the memory test again after the update, at default settings first.
06Understand errors that appear only in the Hammer Test
MemTest86's Test 13 (Hammer Test) checks whether rapidly accessing one memory row disturbs the data in neighbouring rows. Some modules fail only this test.
- If every other test passes and errors appear only in Test 13, note this in your report.
- Check whether your BIOS update or memory kit vendor addresses it, and ask the vendor whether they treat it as a defect.
You know the module is susceptible to disturbance errors rather than failing outright.
If it does not helpSuch modules can still cause rare errors in normal use. For important data, replacing them is the safer choice.
07Replace or claim warranty on the faulty module
Memory that keeps failing at default settings cannot be repaired, and it can silently corrupt files.
- Check the warranty on the RAM vendor's website; many memory kits have long warranties.
- Send the test report and the module details with your claim, and ideally replace the whole kit so the modules match.
- In a laptop with soldered memory, contact the laptop manufacturer's service.
The replacement memory passes several full test passes.
If it does not helpIf new, compatible memory also fails at default settings in several slots, the processor or motherboard is the likely cause; contact their manufacturer.
Possible causes
- Memory overclock profile (XMP/EXPO) or speed the system cannot run reliably
- A faulty RAM module
- Modules that work alone but not together (mixed kits or a heavily loaded memory controller)
- Poorly seated module or a dirty or damaged slot
- Outdated BIOS with weaker memory compatibility
- Less often, the processor's memory controller or the motherboard
Useful Windows tools
These commands open Windows tools. Review changes before applying them.
mdsched.exeeventvwr.mscmsinfo32Was this helpful?
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