Memtest86+, the little RAM tester, flexes FOSS muscles with v7.0

The revival in development of open source RAM-testing tool Memtest86+ continues with version 7.0 – and it's not just for Linuxy types.

Memtest86+ is a FOSS tool for testing a computer's RAM. It's tiny, simple, and has no restrictions on use. If a computer becomes unreliable, a great first step, which doesn't even require opening the case, is to boot Memtest86+ from a USB key and leave it running – ideally, overnight or at least for several hours.

You don't need to install it; indeed, no modifications of the machine's drive are needed at all. It boots and runs directly from a USB key, with no OS underneath, to allow it to test as much memory as possible. The program relocates itself in RAM during operation, so that it can also test the RAM it originally occupied.

Version 7.0 has gained the ability to interrogate the integrated memory controller in Intel Core PCs (first to 14th generations) to find live memory timing information, as well as some preliminary support for obtaining error correction code (ECC) info on some models of AMD Ryzen. However, support for memory error-checking is not a universal option across all PCs, which has been criticized by noted industry diplomat Linus Torvalds, but it seems like it might be staging a modest comeback – at least for AMD users.

Back in late 2022, we cheered the release of Memtest86+ 6.0, which was the first major version in nearly a decade. Version 7.0 is the fourth release since then and it's good to see the tempo of development picking up again.

Memtest86+ the open source project – with a plus sign on the end of its name – is not to be confused with the very similarly named MemTest86, which is proprietary to testing-tool vendor Passmark. There is a freeware version of this, but it's somewhat limited compared to the $52 single-machine-at-a-time version (let alone the $5,000 site-licensed edition). There is a distant link between the two: The FOSS tool originated as a fork of the original Memtest86, which Passmark acquired much later and took commercial. The paid-for tool is now up to version 10.6 and is UEFI-only, although the company still offers the much older version 4 release as a free download for BIOS-based computers.

The open source project has undergone multiple rewrites, as detailed in the README page. Given its tiny size, this is presumably why the homepage now states:

Memtest86+ was once a familiar sight on most Linux distros' boot menus, but it disappeared with the rise of UEFI firmware. That issue went away with the 2022 release, and it has since reappeared in several distros.

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The following year, version 6.10 appeared with added Secure Boot support, although we've seen reports that some people have had problems with that. It's still worth a try, and if it doesn't work, temporarily disable Secure Boot in the firmware settings before testing, and turn it back on afterwards.

It's not really necessary to be able to interpret its results. Boot it, press one key to start a test, and if big red lines appear in the on-screen log saying ERROR, you have RAM issues. Turn the computer off, remove all but one memory module, and try again. Repeat the process until you isolate the bad module.

That is seriously about all there is to it, and sometimes just removing the offending module and limping along for a while with less memory can be a great deal more use than just having a computer you can't use. The Reg FOSS desk has had a few DIMMs suddenly go bad in the last decade: It's a real issue and it does happen.

If you don't have a recent Linux ISO to hand, the project offers its own (absolutely minuscule) downloads that you can simply copy onto a USB key formatted with Ventoy and put to work. The masochistic can, of course, write them directly to suitable media. Incidentally, it works on Intel-based Macs too. ®