find cause of slow Linux desktop?

[straffetoebak]

What are some possibilities of finding out why my pc is slow at times?
It sometimes happens despite it being not old at all and at times when there are no heavy programs running.
I did upgrade the kernel, but within the accepted risklevel, I think.
I also played around with swappiness a bit - the disk is SSD - and I tried very low values, but had to go back up (now at 40).
It is not just eg LibreOffice opening slowly and internet reacting late, but even when typing in terminal it takes some time before the letters show up - not a normal situation.

I used the command screenfetch to get the following info:
OS: Mint 17.3 rosa
Kernel: x86_64 Linux 3.19.0-32-generic
Shell: bash 4.3.11
Resolution: 2944x1080 (I use two monitors - I don't understand where the numbers come from, but I believe the big monitor is 1920x1080 or something like that?)
DE: Cinnamon 2.8.6
CPU: Intel Core i5-3470T CPU @ 3.6GHz
RAM: 4023MB / 7668MB

Any ideas where to start, other than the top command?

[DaveLembke]

Not sure why you had to go in and reduce values. I'd back up your data and rebuild the OS fresh to the system if you were playing around like that. As far as kernels go, I stick to whichever kernel is released for that specific distro release. Going in and altering a kernel or replacing it with another is opening yourself up to problems. Why did you need to upgrade the kernel? I am assuming your running Mint 17.3 with a Kernel that didnt come with the original build?

[straffetoebak]

Not sure why you had to go in and reduce values. I'd back up your data and rebuild the OS fresh to the system if you were playing around like that. As far as kernels go, I stick to whichever kernel is released for that specific distro release. Going in and altering a kernel or replacing it with another is opening yourself up to problems. Why did you need to upgrade the kernel? I am assuming your running Mint 17.3 with a Kernel that didnt come with the original build?

Reducing the swappiness values was because of an article I read about SSD being better of with a lower value than the default 60. A lower value would write less to the disk, which is better for the longevity I understood.

I just checked in the Update Manager (the place in LinuxMint where one can find updates and also kernel upgrades) and it looks like at present the kernel 3.19.0-32 is supported, since apart from Installed, also Loaded and Recommended are ticked.
 

[DaveLembke]

How does the system run without the advanced custom configuration after a clean install? And does the problem crop back up after a specific change to target what the exact cause is?

[straffetoebak]

How does the system run without the advanced custom configuration after a clean install? And does the problem crop back up after a specific change to target what the exact cause is?

The problem is not so big that it forces me to do a clean install, luckily. That is one thing I would like to avoid.
I can't pinpoint any specific action, program or such, that could be the cause 

[straffetoebak]

...I can't pinpoint any specific action, program or such, that could be the cause 

But I was told today that after an upgrade - in my case I had recently upgraded LinuxMint 17.1 to 17.3 - one is supposed to also do a

Code: [Select]

sudo apt-get dist-upgrade which I hadn't done till now.
It looks like this took care of whatever the problem was 
Thanks for your posts DaveLembke - surely appreciated!

[DaveLembke]

Thanks for sharing the solution. When it comes to Linux builds I have always gone with full complete clean builds to avoid problems. Many years ago with Slackware and Redhat I had problems with upgrades, mainly with driver problems such as video driver would go out to lunch and break in the upgrade. So I would have to then fight it out until I fixed it or just give in and go with clean build in which everything works fine. I have been using Linux Mint since version 7, but never did a upgrade from one version to next, the upgrades were always clean installs to avoid version creep etc. I havent upgraded yet to 17.3 I am still on 17.2. With no need to be on 17.3 and games and all working fine on 17.2, I will probably wait for 18 before upgrade by clean build upgrade.