I set up Linux Mint Cinnamon on a laptop my friend gave me with a broken Windows Install. She gave it back to me and told me it was very slow, YouTube videos were stuttering etc.
Now I have it here for testing and for the first 30 minutes everything went fine. Stress test with s-tui and four 4K YouTube Videos in parallel. Unplugged the power, CPU went down a bit but still everything good.
Then from one moment to the other - everything slowed down, while only watching one YouTube video. I checked s-tui and CPU frequencies are down to ~200MHz while load is pretty heavy. Every click has a lag of multiple seconds, I couldn't even open Shutter to make a screenshot as it is not responding.
Anybody any idea what's going on here? Is Cinnamon too much for this device? I am not much of a hardware guy and also don't understand a lot about operating systems, so please be a bit patient with me ;)
Laptop is Lenovo Yoga X1 3rd Gen i7-8550U CPU @ 1.80GHz x 4 16 GB RAM
The CPU speed crashing like that seems like thermal throttling maybe? Any idea on the temperatures? Clean out the vents and redo the thermal paste?
8550U isn't like fast, but is isn't super slow either.
I would also suggest for debugging purposes to re-check on Windows. You can go crazy chasing down a software issue when it's hardware and vice versa. Using a wildly different software stack can point you in the right direction. If the problem persists, it's most likely hardware related.
Temperatures are pretty normal around 40-45°C as seen in the screenshot. Under stress it went up until 85°C, but still normal frequencies and the device was usable.
Throttling seems to be an idea, I found this Git repo, but I have no idea how to confirm this is the issue (and also don't fully understand it), so I'd rather not install it.
With re-checking on Windows you mean create a Windows stick and boot from that (is that possible?) I formatted the drive of the laptop, so no dual boot available..
85C could be throttling
What to do about it?
As others have said, open it up and check the fans.
I'd boot it with it open, my guess is a fan is slow to start because the bearings are worn, and you can see this when booting with the case open.
I've replaced a few on Lenovos over the years, cheap on ebay.