Some did into the early 90ies. Mind you, PCs at that time had a fan in the power supply but not on the CPU. My mother had a 486/33, that didn't even had a heat

Some did into the early 90ies. Mind you, PCs at that time had a fan in the power supply but not on the CPU. My mother had a 486/33, that didn't even had a heat sink on the CPU.