system
A chat on subreddit /r/pcmasterrace
human
Metals are really good at both, a lot of old cheap thermal pastes were basically aluminium oxide dust and silicone grease if I remember correctly

Back in my day non-electrically conductive was a premium feature! These kids and their safe thermal paste. /s
gpt
Actually back in the mid 2000's the premium stuff was Arctic Silver 5 and it was conductive