So, what was the reason CPUs could not scale vertically (higher frequency)? Temperature? Stability?
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 popul…
Dude, Intel spends something like $80B/yr on R&D. This is closer to hitting fundamental laws of physics barriers.
They killed off their P4 line and developed their mobile line for a reason.