Months after first teasing the news, Apple on Tuesday unveiled a trio of Mac desktop and laptop computers powered not by Intel processors, but by its homemade M1 chip, an ARM-based design that more closely resembles those typically found in smartphones and tablets, like the iPhone and iPad. The switch marks the second major change to the silicon powering Apple's Mac lineup, the first occurring in 2005 when the company ditched PowerPC processors for Intel guts.