Question Laptop automatically shuts down (thermal throttling?)

May 27, 2021
TL;DR - my laptop shuts down whenever CPU reaches 70°C, I cleaned the fan from dust. CPU reaches 70°C very quickly after doing almost anything a bit more demanding, if idle, it's stable.

Since yesterday my laptop would automatically shut down without any warning when I do almost anything. I can have only 1-2 chrome tabs open at the time, I can't run antivirus scan or uninstall any programs, if I try to do so, laptop will just shut down.

I don't know why it shuts down or why this happens, before I would be able to have 5-10 chrome tabs open while listening to Spotify and game open in the background and everything would be perfectly fine. Performance would just slow down a bit maybe, but it would never shut down.

I was googling a bit and I came across thermal throttling which is result of CPU overheating.

I opened the laptop and cleaned all the dust, opened the fan and cleaned it as well (there was actually a bit of dust) and it was perfectly clean. I resembled the laptop again (didn't change the thermal paste), but the problem still occurs.

I managed to run a scan on Malwarebytes and there are no viruses or threats. I'm currently monitoring my CPU temperature, it's usually around 50°C, but whenever I try to do something (open a few chrome tabs, watch Youtube video...), temperature would slowly start rising until it reaches around 65-70 before shutting down again.

I read that TJUNCTION for my CPU (i5-4210U) is 100°C.

Now what I'm curious about, how before I was able to do everything and >10x more processes than now, and my laptop would never shut down or slow down a lot, and now suddenly I can't do anything even after cleaning the fan from dust.

I ran Cinebench, not even 5 sec into test, CPU reached 70°C and laptop shut down.
Same with memtest86, it was around 10 seconds before shutting down.

Laptop specs:

MODEL: Toshiba Satellite L50-B-1JJ

CPU: i5-4210U (1.70GHz 2.40 GHz)


Some notes:

Since yesterday (when this happened for the first time) I didn't install or change anything, I was just regularly browsing chrome.

Nothing has been overclocked.

I didn't replace thermal paste.

I used a bit of wipes, q-tips (cotton swabs) and cotton pads to cleanse the fan.

I am using external cooling pad for laptop.

I don't think this is important, but I noticed I have to type A1B2C3 (as a result of getting password wrong too many times, even tho I just turned it on) upon turning the laptop on to log in after shutting down.

Screenshot from Core Temp at the time of writing this: