I need help with my CPU, i don't know what to do!

[JKnow]

So, I've been having a problem with mi laptop, every time i want to play something, a few minutes into a game my cpu reaches almost 80C and clocks down. I tried opening my laptop and cleaning my fans but that didn't solve the issue. I don't know what else to do please help
Sorry for my english, not a native speaker

[2SidedPolygon]

Try undervolting to get those temps down. 80C seems like a pretty early place for it to go ahead and throttle, but not much to be done about that I suppose.

[shark103]

6 hours ago, JKnow said:

So, I've been having a problem with mi laptop, every time i want to play something, a few minutes into a game my cpu reaches almost 80C and clocks down. I tried opening my laptop and cleaning my fans but that didn't solve the issue. I don't know what else to do please help
Sorry for my english, not a native speaker

If you opened it and cleaned the fan then i assume you could also change the thermal paste - did you do it already ?

[JKnow]

thanks for the help! yes, i though about the thermal paste but i'm not very comfortable with the dissasembly of laptops yet, and also it is very difficult to get thermal paste where i live, as unbelievable as that sounds.
i can't undervolt the CPU because the laptop won't let me, i don't know why...

Edit: 
the laptop is a Lenovo Legion Y520-IKBN 80WK

Found this one