> if you ever want to run the machine hard long-term, you can use 1mm thermal pads between the heatsink and bottom of external case (and then it'll never throttle).
That will spread the heat to the battery and degrade it much faster.
This removes heat from the internal compartments (which logic board heat sink and battery co-habitate [0]) by transferring it outside via heat conduction through the case. There is no detectible heat increase (to touch) — consider the heat masses relative sizes (processor v. entire metal case).
That will spread the heat to the battery and degrade it much faster.