Summary: it seems that memtest86+ won't run under UEFI. You need to switch to "legacy" boot and use an appropriate CD/DVD/USB stick to supply memtest86+. I often run memtest86+ when I get new RAM. This increases my confidence that the RAM isn't busted and is compatible with the machine it is installed in. Running it overnight seems long enough without interfering with my use and enjoyment of the computer. I even run it on a brand-new machine as one of the confidence building measures. Well, that's what I used to do. I've not taken the time to do it recently. But I wanted to run it last night because I bought some (mislabelled!) RAM at the NCIX warehouse sale on Saturday. Ubuntu lets you install memtest86+ as a package (it may be a default package, I don't know). But you cannot run it under Ubuntu, you have to boot into it. When you install the package, it adds a grub entry to let you boot into memtest86+ instead of Ubuntu. Yet on my machine there was no such entry. Reading the script that generates the entry, I found that memtest86+ must be booted in 16-bit mode, i.e. old-fashioned BIOS, and not UEFI. So the script doesn't bother to generate the entry on a UEFI system (silently). To run memtest86+, you have to switch the system firmware to use "legacy" booting (old-fashioned BIOS/MBR). On my machine, you cannot enable both MBR and UEFI booting: you need to choose one. Once I switched to legacy booting, I could no longer use the Ubuntu on my hard drive since it was set up for UEFI. I used a Ubuntu installation DVD -- it has an early option for running memtest86+. It turns out that Fedora 21's live/install image has a newer memtest86+ than Ubuntu 14.04: 5.01 vs 4.20. The newer one lists the DIMMs or SODIMMs present on the system.
On Mon, Mar 30, 2015 at 01:24:54PM -0400, D. Hugh Redelmeier wrote:
Summary: it seems that memtest86+ won't run under UEFI. You need to switch to "legacy" boot and use an appropriate CD/DVD/USB stick to supply memtest86+.
Yes I see memtest86 does work with UEFI, but memtest86+ does not. But memtest86 seems to have stopped being open source at version 5 which is when they added UEFI support as far as I can tell.
I often run memtest86+ when I get new RAM. This increases my confidence that the RAM isn't busted and is compatible with the machine it is installed in. Running it overnight seems long enough without interfering with my use and enjoyment of the computer.
I even run it on a brand-new machine as one of the confidence building measures.
Well, that's what I used to do. I've not taken the time to do it recently. But I wanted to run it last night because I bought some (mislabelled!) RAM at the NCIX warehouse sale on Saturday.
Ubuntu lets you install memtest86+ as a package (it may be a default package, I don't know). But you cannot run it under Ubuntu, you have to boot into it. When you install the package, it adds a grub entry to let you boot into memtest86+ instead of Ubuntu. Yet on my machine there was no such entry. Reading the script that generates the entry, I found that memtest86+ must be booted in 16-bit mode, i.e. old-fashioned BIOS, and not UEFI. So the script doesn't bother to generate the entry on a UEFI system (silently).
To run memtest86+, you have to switch the system firmware to use "legacy" booting (old-fashioned BIOS/MBR). On my machine, you cannot enable both MBR and UEFI booting: you need to choose one.
Hmm, interesting. I think every machine I have ever used supported having both at the same time and you could choose which it should try first.
Once I switched to legacy booting, I could no longer use the Ubuntu on my hard drive since it was set up for UEFI. I used a Ubuntu installation DVD -- it has an early option for running memtest86+.
The new machine I got at work actually lets you pick UEFI or legacy for each boot device in the system, which is rather nice of it. Makes things much simpler.
It turns out that Fedora 21's live/install image has a newer memtest86+ than Ubuntu 14.04: 5.01 vs 4.20. The newer one lists the DIMMs or SODIMMs present on the system.
5.01 certainly is the latest version. -- Len Sorensen
D. Hugh Redelmeier wrote:
Summary: it seems that memtest86+ won't run under UEFI. ...
Just as another data point, it seems to not run under PXE either, even on a few-years-old pre-UEFI box. An older memtest image did boot okay, but was too old for something in that box's architecture. At the time I chalked it up to probably depending on something in a GRUB boot environment and moved on, so I'm not sure there's a solution. -- Anthony de Boer
participants (3)
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Anthony de Boer -
D. Hugh Redelmeier -
Lennart Sorensen