Technically it was heat but mostly it was due to (i) Economics, there was less demand for faster clock speed. Otherwise more research could have gone towards solving heat problem. (ii) Each cycle of CPU was more efficient with ability to execute multiple instructions in a single cycle and with more efficient instruction sets.
Surprisingly, power consumption also made huge impact. As tablets and laptops got more popular than desktop battery life became a major concern and thus TDP played major role in research.
Try this fun experiment: Underclock your CPU by half a GHz and see if you notice the difference in your day to day work.
Surprisingly, power consumption also made huge impact. As tablets and laptops got more popular than desktop battery life became a major concern and thus TDP played major role in research.
Try this fun experiment: Underclock your CPU by half a GHz and see if you notice the difference in your day to day work.