How to Test RAM: Making Sure Bad Memory Isn't Crashing Your PC

how to test ram

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Your computer's RAM is key to its operation. Explained simply, RAM (opens in new tab) is your computer's short-term memory, which it uses to work on its current task. However, like any computer part, even the best RAM (opens in new tab) can break, so you'll want to know how to test whether your memory is stable or not. 

One of the first signs of memory going bad is blue screens of death (BSODs). Memory issues often make themselves easily noticeable by their rapidly increasing severity. At first, you'll only rarely experience crashes, and the system will still be workable. But before you know it, the system will crash during start-up. Therefore, it's important to identify the problem quickly.

There are multiple ways of testing your computer's memory. We'll cover a few of them today. 

How to Test RAM

how to test ram

(Image credit: HCI Design)

One option preferred by us at Tom's Hardware is HCI Design's MemTest (opens in new tab). The good thing about this is you don't have to any pre-booting and there are no directions. You just run it. 

How to Test RAM With Windows Memory Diagnostic Tool

The next easiest way to test your memory is with Windows 10 (opens in new tab)'s built-in Memory Diagnostic tool. 

1. Search for "Windows Memory Diagnostic" in your start menu, and run the application.

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2. Select "Restart now and check for problems." Windows will automatically restart, run the test and reboot back into Windows.

(Image credit: Tom's Hardware)

3. Once restarted, wait for the result message. This may take a few moments to appear as the system starts up. Be patient. It will show up, but keep an eye out for it, as it will disappear again quickly. 

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How to Test RAM With Passmark Memtest86

PassMark's Memtest86 is a reliable tool for testing memory without the need for an operating system, meaning it will work on Windows machines as well as Linux computers. It runs off a bootable USB stick, and although it looks complicated, it is very straightforward to use.

1. Download Passmark Memtest86 (opens in new tab).
2. Extract the contents into a folder on your desktop.
3. Insert a USB stick into your PC. Back up any data on it, as Passmark's tool will format the USB stick.
4. Run the "imageUSB" executable.
5. Select the correct USB drive at the top, and press 'Write'

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6. Double-check whether everything is correct before proceeding. Writing will take a few moments, depending on the speed of your USB stick.
7. Restart your computer, and enter the boot menu through pressing F2, Del, F8, F10 or whichever key your system uses. It will say on your post screen.
8. Boot off the USB stick.
9. Press "Config."

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10. Select "(S)tart Test" in the Memtest86 home screen.

(Image credit: Tom's Hardware)

Now let the application run the test until completion or until errors appear. You can monitor the progress of the test at the top of the screen.

Depending on your memory size, testing can take from 20 minutes to a few hours. If errors appear, there is no point in continuing testing. A screen with errors looks like this:

(Image credit: Tom's Hardware)

What If My RAM Is Bad? 

If you didn't get any errors: congratulations. Your memory is in working order. You can either rest assured or, if you are having crashes, continue troubleshooting to figure out what else may be the cause now that RAM issues are ruled out. 

If you do get errors, then also congratulations: you've found the culprit of your crashes. In 95% of cases, the only way to fix memory issues is to buy new RAM (opens in new tab) or replace it. If you have multiple RAM kits, be sure to test them independently to figure out which is causing problems and send it in for warranty. Luckily, a lot of RAM kits come with a lifetime warranty these days.

But there are three things you can do to try to get rid of these RAM-caused issues. 

The first is to ensure that your RAM is running at the correct clocks for your system. All memory has its speed and timings written on its label or packaging, and you want to make sure that it runs at these speeds using the XMP profiles in your BIOS (opens in new tab). It hardly ever happens, but it's possible that the memory was set to run faster than it was capable of, which would naturally lead to errors.

If setting the right XMP profile in your BIOS doesn't help, another trick that sometimes works is to underclock your memory -- i.e. run it slower than the intended speeds. You can do this by reducing the frequency and backing off on the timings. However, this is often a temporary measure because if the RAM has degraded, the errors are likely to return soon.

Lastly, note that certain platforms do not play nicely with all memory configurations. If you're running an especially high memory frequency, be sure to check whether this is supported by your CPU (opens in new tab) and motherboard (opens in new tab). Out-of-spec combinations will make it appear like the memory is broken, when in actuality the memory controller on your CPU is unable to handle the RAM's high frequencies.

Niels Broekhuijsen

Niels Broekhuijsen is a Contributing Writer for Tom's Hardware US. He reviews cases, water cooling and pc builds.

  • mitch074
    I recently had problems with brand new DDR4-3200 ram that caused BSOD. I overvolted it by 0.01 V and then everything was right.
    The problem can also be improper voltage delivered by the motherboard. Such an overvolt is well within tolerance margins and can save you quite some headache.
  • R_1
    mitch074 said:
    I recently had problems with brand new DDR4-3200 ram that caused BSOD. I overvolted it by 0.01 V and then everything was right.
    The problem can also be improper voltage delivered by the motherboard. Such an overvolt is well within tolerance margins and can save you quite some headache.

    yes. I had an ASUS board with MEMok and it set the RAM voltage too high, but it worked, when I finally found out a year later or so and set the RAM to stock, bluescreen city.
    double check the voltages of your RAM.
  • bit_user
    I've long been a fan of Memtest86, now owned by PassMark. I recommend running at least two full passes. Ideally, after installing or changing your memory configuration, just let it run overnight.

    The reason is that I've seen memory test fine, in the first pass, but encounter errors in subsequent passes.
  • MaCk0y
  • PMKing
    I have a rebuilt desktop but Windows 10 won't install on a clean hard drive it stops at 5% when getting things ready.
    I found a few workarounds online none of which work and have since found a how to test RAM from command prompt.
    I have 2 4gb RAM modules and obtained the following information. It's the same on both banks.

    BankLabel=BANK 0
    Description=Physical Memory
    Device Locator=Channel 1B-DIMM0. (BANK 2 has Channel 1B)
    Manufacturer= Micron. (BANK 2 has Samsung)
    Name = Physical Memory
    PartNumber=16JTF51264AZ-1G4M1. (BANK 2 has M378B5273DH0-CH9)
    Powered On=
    SerialNumber=31877266. (BANK 2 has 647E6513)
    Tag= Physical Memory 0. (BANK 2 has 2)
    Total Width=64

    Can anyone tell me what I've missed here. As far as I can tell everything else is fine.
    The machine has a new motherboard, PSU, Hard drive. Beforehand the memory was working, the machine had a motherboard failure caused by faulty PSU.

    Many thanks.