In 2020, I was doing a lot of video encoding on my Surface Book in India in ambient temperatures in the range 25–35°C, and I found that lying its heat source down on a marble floor sped it up by 60% within a minute or so, the floor acting as a large heatsink.
(I also learned that the Surface Book has a dedicated “I have shut down because I overheated and must cool down before I will start up again” screen (an illustration of a thermometer), which I wouldn’t expect most computers to have, though I think I’ve only caused thermal shutdown one other time; during Hyderabad summer, recording in the late afternoon in an upper room, the ambient temperature got as high as 45°C, and there wasn’t enough thermal headroom for throttling to save it, so it needed extra makeshift external heatsinks. I quoted 25–35°C in the first paragraph because I was doing the actual editing overnight when it was somewhat cooler.)