Yeah, my old Commodore 64 had a blinking cursor, and it somehow managed that remarkable feat with an 8-bit 6510 CPU running at 1MHz!!!
...though, to be fair, keyboard input on those old 8-bitters was usually a busy loop of some sort (looks like
LOOP LDA $C000
That's 100% CPU usage right there, though without a need to share it with other processes (because there were no other processes), the concept is somewhat meaningless in this context.