Buster freezes often on two different systems

[Onsemeliot]

I am using vanilla Debian stable on two different laptops and recently I often get complete freezes. (Nothing does anything. Not the keyboard nor the mouse.) When it occurs I can only switch the system off via the physical power button. I wonder if anyone else is having such issues recently. I can't pin-point specific circumstances. It doesn't happen when the system is freshly started but it doesn't need to run much or edit very heavy files. I would first suspect my dated hardware but the fact that I keep getting those freezes almost daily on different laptops seems to hint a software problem instead of a hardware issue.

On 8 GB of RAM GNOME should run fine:

I use Technoethicals' T400s and the other system is a Fujitsu-Siemens Lifebook e781 vPro. I would be able to test Debian Buster with LXDE on an Acer Extensa 5220 and on an IBM ThinkPad T40 also but those systems are even more outdated and therefore hardware issues are rather likely. And testing them needs a lot of time since the freezes don't occur regularly on the first two systems. It can be more than once a day but it can also be some days (having switched the device off over night) before a system freezes again. The two weaker/older systems are meant as rapid replacements in case of an urgent need. They are rather slow and therefore are not very comfortable for the graphic design work I am doing.

I suspect either GNOME or systemd because the applications I run don't seem to matter much. But if I am the only one noticing such problems recently then those two suspects become much less likely sources for my problems ...

[Head_on_a_Stick]

CPU µcode?

[Onsemeliot]

You think that would be a reasonable explanation even if this didn't happen with older versions of Debian on the same laptops?

[Head_on_a_Stick]

Perhaps not but is it installed?

What do the logs say about the freezes?

[Onsemeliot]

I have to wait for an other freeze because I can't remember when the last one actually was in order to sensibly search in the logs right now. But I definitely didn't install any non-free packages. I will check again if I can find BIOS updates.

I totally forgot that on my T400s I have Libreboot instead of the normal bios. Therefore, I guess there isn't anything that I could do on that level.