For the last week or so, the same issue of lag between my typing and the screen catching up has appeared on both a desktop PC running Xubuntu 20.04, and also a laptop running 22.04. Both machines have all software updates, including some installed before and since this issue appeared, both worked without issue previously.

This happens on every application, too. Whether trying to type into the search bar of any browser, do any kind of typing into Thunar, or even typing in the terminal - it can take anything up to six seconds for what I write to appear on the screen.

Clicking the Whisker menu icon also freezes the screen (I think it puts it to the background as it should) but doesn't display the menu itself until I move the mouse over the specific area of the screen where it should appear (moving the mouse anywhere else doesn't result in the menu appearing, nor the underlying screen unfreezing).

I don't know where to start in trying to diagnose this and I can't find any reference to others who might be experiencing something similar recently.

Any help very gratefully received!

1: If Xubuntu has a process monitor, check it out and try finding something that may be hogging resources, CPU usage and memory

2: If your machines have discrete graphics devices, have a look at Ubuntu drivers/Driver manager app to see if necessary drivers are installed, shouldn't hurt anything uninstalling, reboot and reinstalling if they are installed.

3: The cryptocurrency world has been going through some rough times recently, some large crypto mining firms have declared bankruptcy. In the early years of Bitcoin, miners mostly used other peoples or large firms/government computers that ran continuously to mine Bitcoin via internet without permission. This would have those computers using near maximum resources. Nowadays there are hashrate calculators to find the cost of mining cryptocurrency. With the current unstable situation in the crypto world, it is possible miners are resorting to the old way of mining, which cuts costs to near nothing on their end, by using your computer to mine cryptocurrency.

Hello, I was using a 20.04 and now a xubuntu 22.04.2 LTS.

The advice already given may have already helped to solve the problem.

In a terminal, use the command.

It is possible that process systems write a lot of logs.
This can have an incredible slowing down effect.