By the time Intel sold > 66 MHz 486's, the Pentium was already out. They remained a low end alternative, but still topped out at 100 MHz. AMD took their 486 clo

By the time Intel sold > 66 MHz 486's, the Pentium was already out. They remained a low end alternative, but still topped out at 100 MHz. AMD took their 486 clone (called the 5x86) eventually up to 150 MHz.