If I encounter a situation where I suspect my machine's RAM might be going bad, I might need to launch memtest86+ to check it. How can I do this using Ubuntu? Are there different methods for launching it whether Ubuntu is already installed?

* (This is intended to be a canonical question easy for new users to follow.)

  • 3
    I would suggest running it overnight if possible. I had long running problems caused by faulty RAM and it took 11-12 hours of testing before the errors appeared.
    – JohnW
    Commented Mar 3, 2015 at 19:38

4 Answers 4


memtest86+ comes default with Ubuntu and you can try it from live CD or from any installation of Ubuntu. Here are the steps:

  1. While booting press (better hold down) the Shift key to bring the grub menu that looks like the following image:

    entering grub

    As you can see there are some options to choose from (this will vary from installation to insatllation), the one to look for is the third option in this screenshot i.e. Memory test (memtest86+), which will be there in the grub menu along with other options.

  2. From the grub menu go to the appropriate option to select i.e. Memory test (memtest86+) and press Enter.

    select memtest

  3. Now you will see a blue screen indicating that the memtest is running:

    memtest running

  4. Now you can press c for more configuration options:

    selecting conf options

  5. To exit from the memtest86+ session you can press Esc any time. There is no certain rule that how many passes you would run but the more the better.

Here is an image (taken from here) showing that errors were encountered i.e. the test is failing in some memory locations (pointed out in the red portion) indicating the locations might have problems. If your memory does not have any problem then you won't get any red portion.

error message

  • 14
    I know this is an old thread but just in case someone is still paying attention: any idea how to get the memtest option in the grub menu for 64 bit / EFI systems?
    – ElRudi
    Commented Aug 21, 2016 at 19:25
  • 8
    @ElRudi the latest version is available here and supports UEFI memtest86.com/download.htm How to add it to the menu is here askubuntu.com/questions/126160/…
    – Elder Geek
    Commented Aug 23, 2016 at 23:11
  • 1
    The faulty RAM photo is very helpful. Without it, I don't know whether my RAM is okay or not. Thank you. Commented Feb 10, 2022 at 23:52

To perform a memory test on Ubuntu Live CD and Installed system:

  1. Turn On or Restart the system.

  2. Hold down Shift to bring up the GRUB menu.

  3. Use the arrow keys to move to the entry labeled Ubuntu, memtest86+.

  4. Press Enter. The test will run automatically, and continue until you end it by pressing the Escape key.

Allow the test to run for at least one full pass.


My Ubuntu 20.04 system with 128 GB RAM became very slow after I had to reload the OS. I thought it could be a bad memory. I checked the memory using the following command,

    sudo memtester 128000 5

Doing the following solved the issue (in case it is helpful for others),
Changing the NVIDIA driver for the graphics card from opensource to proprietary did the magic. Following also helped.

    sudo vi /etc/sysctl.d/99-sysctl.conf

and add the following,



To use Ubuntu live USB for starting memtest86+ you might have to change boot order in BIOS or press some system specific (function) key to display one time boot menu and then (at least with Ubuntu 22.04 live media) choose legacy boot (not UEFI) for the USB media. Then there is Memtest in the Grub menu. Maybe with the latest Ubuntu release it is different and you can run memtest even if you use UEFI boot for the media since memtest86+ version 6 has UEFI support.

  • 2
    Yes, memtest86+ version 6 has UEFI support. You can get it as a separate tool or as part of a live or persistent live Ubuntu [flavour] made with mkusb 'dus-iso2usb'. - So you can use it in UEFI mode even without the newest versions of Ubuntu [flavours].
    – sudodus
    Commented Oct 24, 2023 at 22:37

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