Linux

you're nowhere close to RAM exhaustion. I had similar mishaps on an all-AMD system a few gens back and it manifested itself as micro-stutters that occasionally grew to such manifestations. I think I remember it was a combination of kernel switches and progressively better performance as new versions of kernel and modules/drivers progressed.

no idea what KDE Neon is based on (Ubuntu LTS?), but I'm guessing you rock pretty old kernels and relatively modern hardware, which is a pain. also you don't need a swapfile, use zram. or just switch to fedora or sumsuch that takes care of all them things for you.

I seem to remember having similar issues on Neon, back shortly after it came out. I chalked it up to it being bleeding edge'ish, went back to Kubuntu and then Debian.

This looks like either a driver issue, but more likely, a hardware issue. Either your nvme, or your RAM, is faulty. Run memcheck (it's a bootable thing you run to make sure your ram is ok), and I'm sure there are tests for ssds too.

If your DE/Launcher uses systemd scopes properly you might be able to see something in the journal. As an example somewhere in my logs I can see this:

Jan 17 17:52:50 sky systemd[2171]: app-niri-steam-40213.scope: Failed with result 'oom-kill'.
Jan 17 17:52:50 sky systemd[2171]: app-niri-steam-40213.scope: Consumed 6h 32min 39.773s CPU time, 9.4G memory peak, 6.2G memory swap peak.

That's pretty clearly severe thrashing and an eventual OOM event caused by a game. If you're not familiar, the command journalctl -e -b -1 gives you the last log lines from the last boot. Use d and u to navigate the pager and q to quit. This will only work if the launcher you are using sets up transient systemd scopes and doesn't just fork-exec into the application (Fuzzel does the wrong thing by default, as do many others).

I've also seen large Steam downloads causing such issues, so capping your download speed might help. As could enabling ZRAM.

Edit: Also, this is most likely completely unrelated but do note that Neon is basically abandoned. You should very much consider switching to a maintained distribution, whether that's another Ubuntu spin or Fedora or something else entirely.

In addition to all the good suggestions already here, consider installing early-oom and configure it to kill the stuff you care less, maybe one of those heavy electron-based clients.

When this happens, can you switch console (ctrl-alt-f1) or restart X (ctrl-alt-backspace) or can you ssh from another PC? you can also in a window have a journalctl or something tailing the logs and see if something is happening there

Ok so I kinda had a similar problem. Difference is that I was using Arch and full disk encryption. System would freeze up if I tried writing big files and disk light would start blinking.

It might not be that to so maybe run "journalctl -b -1" the next boot after your system freezes and check towards the bottom of the log to see if there are any errors, usually red. Another way is to use btop running in the background and when the system gives any sign that it'll freeze switch to btop and check what's going on.

Edit: something that came to me is to try to switch to another tty using Ctrl+alt+number, I'm not sure how neon works so try 2 or 3 or 4.

It may not be the raw RAM usage.

My first suspect is the Windows VM especially if it's running enterprise security software 4GB is probably not enough for modem Windows and it could be trying to use its page file, thrashing your disk in the process.

Are you able to collect some data from system monitor on paging and disk activity? That could help you narrow it down. You can use btop for a quick terminal option if your gui is non responsive (assuming your could switch to a console). Vmstat is another option that you can run in the background to collect stats over time, but it's not user friendly.

Neon doesn’t force you to actually update the ubuntu it’s built on unless you manually do it iirc. Update your shit and report back.

Once you decide not to try that, top, btop atop or htop can tell you the amount of ram you’re using. They will all also tell you how your disk writes are doing.

It doesn’t sound like you have a ram issue, it sounds like you have a disk issue. First and foremost, once you’ve verified that you have plenty of memory available using a tool described above, expand your windows vm to 8gb. Windows would aggressively page if it had only 4gb and windows in a vm will also aggressively page when it only has 4gb, except it has to go through kvm to access those qcows.

It sounds like you have way too many tabs open. Close some and see if that helps you out. You can highlight a bunch of them by selecting one and ctrl-shift clicking on another one to get every tab in between. Right click and add to bookmarks then close them.

Next, use spinrite with I think a level 3 scan on all your nvme drives. It shaves a write cycle off the top (you have hundreds of thousands at the very least) but in return makes everything fast again. Flash memory becomes less responsive as read cycles on a block pile up until it’s rewritten.

Try different USB devices. I had a bad mouse do something similar.