Help with old PC which got very slow after a few months of no use

Help
1

Hi all,

I have this older 8-yr-old PC which I didn’t use for a few months and when I recently turned it on, it was dreadfully slow. It dual boots Windows & Kubuntu. Kubuntu was my main driver for 7 years, then I switched over to another laptop for work. For those 7 years, Plasma was smooth and solid. But after these few months of not using it, it has become unusably slow. For example, opening the menu takes 2 seconds, Dolphin and Kate take 4 seconds, Libre Writer and System Monitor take 10-14 seconds. Very often a click or shortcut lags for a second or two.

I’m not sure what has gone wrong. I did all the updates, upgraded to 24.04, and uninstalled a bunch of apps I was not using (upgrading via terminal took well over 8 hours). I also checked the System Monitor and it shows low CPU & memory usage. I have no idea why this system is so slow. I am close to formatting and reinstalling another KDE distro, but is there anything I could do right now to save this installation?

Specs:

  • Intel Core i5-6200U (6th generation i5 that’s dual core 2.3Ghz each), 16GB RAM, 512GB SSD, Intel HD Graphics 520
  • Kubuntu 24.04, KDE 5.27.11, Qt 5.15.13
  • Home and root are in different partitions (I think I did this so that I can reinstall more easily without losing files), and there is a separate Windows partition. Home is 60% full and root is 70% full.

Many thanks in advance!

2

A common cause of things being slow is IO (so data being written or read from disk).
In htop, you can add a “Disk IO” meter that helps to figure out if this is an issue.

I don’t know why this would suddenly start, but htop also has a screen for figuring out which process is causing it.

3

Thanks. I’ll check it out. Just to understand - I add this to htop, look for IO anomalies, and troubleshoot from there?

4

Hi bokbokwhoosh

Try a live OS as a first step before trying to fix something that may not be borken.

Vektor

5

First thing to check is the hardware:

  • Have you really got 16GB of RAM or has some been disabled due to errors. This would also show has swap usage.
  • Any disks problems (what is reported by SMART tools?)
  • Is the CPU running at its max frequency with all its cores and what is the temperature? If cooling becomes marginal (dust, thermal paste) the CPU can heat up and throttle to avoid temperature damage. Power management could also be trying to keep your PC in “power savings” mode (essentially low CPU frequency).
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Thank you. Yes, my RAM shows a usable portion of 14.5GB. Temperature is normal. It rises a bit when the CPU runs more, but it’s still quite normal. I do have powertop. I had just installed it and I had thought of it as a ‘set it and forget it’ kind of thing, had not edited configs.

7

Thanks for these suggestions! I used GSmartControl to run the extended offline test, and it came out okay. I monitored temperatures for about an hour and the highest it went was around 65 degrees celsius. Mostly it hovered around 50-55 degrees. Arguably, I didn’t run it to a max frequency, just everyday things - a few tabs on Firefox (including a video on youtube), Thunderbird, Libre Write open, running these tests…

Edit: So, I went off on a hunch and disabled Akonadi. I’m not sure what was happening, but this did the trick! Back to all smoothness now. Dolphin and kate opens in almost a second, Firefox in less than 2 seconds. Thanks for the input all! If you know what happened here, do let me know. For now, I can continue using this PC for minimal tasks.

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