all hardware comes stock at like 50% its real power. its to allow plenty of space for accidental overages, and avoid forget ups, and the company can avoid tons of factory warranties being used.
a smart pc user wants to use that hidden power. but you need a slightly bigger power supply, and very good cooling. the only 2 limits to pushing hardware harder (other then parts bottlenecking each other, technically you can still overclock them, but you wont feel the extra power)