[aurizon]

open up, remove heat sinked parts, clean both faces with isopropyl alcohol. Buy some 'cooler master' paste and reseat. Take care with minimal alcohol and power off - it can catch fire. Most repair shops can do this - ask first

[GWBullshit]

Thank you for the reply and advice – I will probably pursue this if it keeps up, even though it seems to have happened much more dramatically after the last OS update.

Regardless, I'm still unsure how it can read these temperatures since the "put in freezer for a while" method seems to work when it does this and everything gets "un-sluggish" right away and starts working as well as if I restart it, no matter how many things are open.

So it's like the processor "works as if it wasn't overheating", but for some reason the temperature readings for things like synching sometimes don't work because it reads the temp as approaching ~200º, and even external apps read it as such (though I realize they may just be repeating an internal OS error).