DigitalDilemma

I’m guessing you’ve already turned it off and on again. If not, seriously, do that. It works more time than it doesn’t for random weirdness.

Run ‘htop’ and sort by CPU (it’s a friendlier and better version of ‘top’. That’ll show you what processes are using the most CPU

Whilst you’re in there, check the free memory. If that’s low, or swap usage is high, then use htop to sort by memory usage to find what’s using the most.

If you see processes you don’t recognise, hit google and find out why. It’s very unlikely they’re malicious, but it’s far less common on linux than Windows to have random processes doing unknown stuff. If it’s using a lot of cpu or memory, there’ll be a reason. It might be a dumb reason, but you will be able to find it out.

And then when you know what the guilty process is, if it is that, and it’s not critical - you can stop it with systemctl and narrow down what’s afoot.

Gosh, I wonder what stirred them up?