If default clock speed = 600Mhz, and for certain process, it takes up constant 100% usage over a period of say 10s?

VS

clock speed = 900Mhz, and for similar process, it takes up constant 100% usage over a period of say 3s?

Base on above, does it mean OC is better?

On another hand, if running apps like PSX4ALL over long periods say 1hr, the impact/damage will be on 900Mhz?