Memtest86+ is a stand-alone memory tester for x86 and x86-64 architecture computers. It provides a more thorough memory check than that provided by BIOS memory tests. Memtest86+ can be loaded and run either directly by a PC BIOS (legacy or UEFI) or via an intermediate bootloader that supports the Linux 16-bit, 32-bit, 64-bit, or EFI handover boot protocol. It should work on any Pentium class or later 32-bit or 64-bit x86 CPU.
Licensing General Public License v2
Memtest86+ v6 is an unified, free, open-source memory testing tool, released under GNU GPL v2.0. The new v6 code base (originally called PCMemTest) was provided by Martin Whitaker, based on Memtest86+ v5, developed by Sam Demeulemeester. Both are now working on Memtest86+.

Memtest86+ is unrelated to 'Memtest86', a closed-source `Freemium` software released in 2013 by PassMark Software Pty Ltd.

Why test your RAM?

ram logo
Troubleshoot PC Instabilities
Memory errors are one of the most common causes of crashes, freezes and instabilities. If you encounter such issues with your computer, testing your RAM thoroughly is probably the first thing to do. Memtest86+ uses various algorithms to reliably detect failures. It will let you know if your RAM is faulty or not.
Ensure Initial Stability
Before using your brand-new PC, putting your new server into production, or after having overclocked your CPU or RAM, it's often wise to make sure there is no memory issues. Troubleshooting issues later can be annoying, costly, and time-consuming.

Frequently Asked Questions (FAQ)

This FAQ covers the main issues with Memtest86+. Please also read the full README if you don't find an appropriate answer.

Installation on Removable Media

How to create a bootable Memtest86+ USB Drive using Windows?

Plug a standard FAT32-formatted USB Drive, download and launch the Windows USB Installer and follow the quick steps. Reboot your computer and select the USB Drive in your Boot Menu.
The ISO image must be written directly ('dumped') to the raw device, either by using the dd command or by using a utility that provides the same functionality like balenaEtcher.
We recommand balenaEtcher to burn the image to an USB Drive under MacOS. PS: Using the Restore function in Apple's Disk Utility does not work.
Memtest86+ can be run from an USB Key (FAT32 formatted), CDROM drive (by burning the ISO to a blank disk) or Network boot (PXE). If you need a floppy image, use the "make iso" command to generate a 'floppy.img' file

Booting Issues

I can't boot because of a "Secure Boot Violation"

The Memtest86+ binary is actually not signed by Microsoft, so you need to temporarily disable Secure Boot in your BIOS options. We're working on a better solution.
To boot on a USB Key instead of your hard drive, you must select it using the Boot Menu. The Boot Menu is usually available by pressing F8, F12 or ESC at early startup. Please check your PC/motherboard manual.
Yes. Just use memtest.bin (for BIOS PXE) or memtest.efi (for UEFI PXE) as payload for iPXE or PXELINUX. Don't forget to disable Secure Boot.
Memtest86+ USB drivers are work in progress. Not all USB devices are supported yet, and there may be problems on some hardware. Please submit a bug report with detailed information.

Troubleshooting RAM Errors

I got errors! What's next?

Once a memory error has been detected, determining the failing module is not a clear-cut procedure. If your computer is overclocked, you should try again at default settings first. Then, if you have more than one memory module, try removing them one at a time to find the faulty one. You can also rotate them. For more informations, look here
Yes. Both Linux and Windows offer a way to exclude small bad memory areas. An additional Memtest86+ feature is planned to easily generate the required patterns for Windows.

Various

When does it stop?

It doesn't: Memtest86+ is an endless loop. After a successful pass, all your memory has been tested successfully. You can wait more for even greater confidence, or just remove your USB Drive and press ESC to stop.
For a more detailed explanation about Memtest86+'s Test Algorithms and induvial Test Descriptions, please check this section of the README page.
On Windows, edit the file syslinux.cfg at the root of the USB Drive and add "APPEND ttyS0" after "KERNEL mt86plus". On Linux, pass the parameter "ttyS0" using GRUB ISO. Alternatively, compile your own version with the switch "enable_tty = true" in "config.c. Default settings are 8N1 115200 bps.
It doesn't. The memory on a modern computer is not necessarily mapped in a linear way. Ie: 16GB of RAM can be virtually mapped from 0-15GB and 16-17GB with a hole between 15GB and 16GB.

Download Latest Version

Memtest86+ v6.00 Beta 1
Released: 2022-05-02
v6 is NOT READY for production yet!
Please consider the actual code as experimental and expect crashes and freezes. First non-beta release is expected this summer.
Icon
Windows USB Installer (32/64 bits)
b6e134cb302e9934840712f366ab5102
Icon
Linux ISO (32 bits)
f54a054c92d90824bb88324e831bfe62
Icon
Linux ISO (64 bits)
e6449c251f8f3b942dd7b7272328d68a
Icon
Linux ISO w/ GRUB (64 bits)
9c80a0510e0f4370d3c3b769d5fa8b1a

Changelog

  • Rewrite code for UEFI 32 & 64 bits
  • Add support for x64 Long Mode Paging
  • Add support for up to 256 cores
  • Add detection for DDR4 & DDR5
  • Add support for XMP 3.0
  • Add detection for AMD Zen 1/2/3
  • Add detection for Intel up to 13th Gen
  • Add support for native USB keyboards
  • Add detection for Rambus RDRAM
  • Add detection for Zhaoxin CPUs
  • Numerous bug fixes

Memtest86+ Timeline Evolution of the GPL version

Memtest86+ V6
M. Whitaker & S. Demeulemeester
2022-
PCMemTest
Martin Whitaker
2020-2022
Memtest86+ V1-V5
Sam Demeulemeester
2004-2020
Memtest86 V3
Eric Biederman
2004
MemTest-86
Chris Brady
1994-2002

Bug Report

Found a bug? Please fill a bug report on our official GitHub page!

Please give us as much information as possible about your hardware and the way to reproduce the issue. Also, please check that your bug hasn't already been submitted.

Donation & Last Donators list

Robert Dixon
Donated $50 on 2021-11-29
Brandon Lancaster
Donated $50 on 2021-11-28
JaWo Webdesign
Donated $10 on 2021-11-21
Link
Svilen Dramov
Donated $10 on 2021-11-20
Monovm
Donated $10 on 2021-02-07
Link
Jessie Clarcson
Donated $10 on 2020-09-15