[pjc50]

Computers more than ever rely on not being at 100% CPU all the time, because the increased power consumption and heat dissipation is a problem. Instead it's all about the "race to idle": do the work and then go to sleep for a few miliseconds to cool down.

[reubenmorais]

Case in point: with my MBP battery, I can get 8 hours of browsing the Web, reading articles, watching a YouTube video or another. But if I spin a parallel build that uses 100% of all cores for about 15 minutes, I eat through half of my battery life.

[agumonkey]

I wonder what's the sleep-state/consumption curve. Linear or not.

[userbinator]

The difference between idle and full power is very large in modern CPUs - a typical laptop one can consume an average of a few watts at idle, but several dozen at full load; furthermore, they can switch between these states thousands of times per second. This is why CPU power circuitry is not easy to design, since it has to keep up with the very fast changes in current as the CPU transitions between power states.

Incidentally, this is also why you may be able to hear audible sounds from a computer when it's idle or running some particular process - the wakeups/sleeps are happening at a frequency in the hearing range, and the components like capacitors and coils can act as tiny speakers.