Hello everyone!

I have a thinkpad t420 (without a discrete gpu) and I am hitting up to 95℃ on a full cpu load (for example, writing large files to a zstd=15 btrfs filesystem on a LUKS volume), even in my very cold room (I am wearing three sweaters as I'm typing this). Everyday tasks like watching videos bring me up to around 65℃. I got this laptop second-hand, but pretty sure the former owner has never repasted it.

So, is it a good idea to replace the thermal paste to improve cooling? If so, what thermal paste should I go with? I have Arctic mx-4 on hand, would that be an improvement? What about liquid metal?

Also, for my own understanding, I would be grateful if someone answers these questions: does thermal paste "dry out" over time? Is there such a thing as a "bottleneck" when it comes to cooling? For example, could it be that upgrading the thermal compound won't yield lower temps, because the heat pipes or the fan are the bottleneck?

Thank you in advance.

EDIT: I disassembled the laptop, cleaned out the fan/finstack with a hair dryer (on no-heat setting while holding the fan in place), cleaned out the old paste with ear swabs and rubbing alcohol (although isopropyl alcohol would have been better), and applied a fresh portion of arctic mx-4. I tightened down the cooler, then removed it again, covered up a little corner of the die that didn't get covered, and tightened the cooler down for the final time. Now I don't go above 78℃ even when doing an all-core torture test with mprime (in the same cold room). Thank you to everyone that helped!