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Fantasy

Intel Turbo Boost technology is similar to this. CPU clock rate will be dynamically changed to cope with the task. In mobile processing, it is even more important to control the power and heat. For a very short time, the CPU can run really fast. However, if task time is long, the power has to be dropped to avoid too much heat generated.

haboric

Indeed, Intel Turbo Boost technology is a good analogy to this. Through dynamic control of the processors' clock rate, Intel Turbo Boost enables them to run above the base operating frequency. However, processors' power, current limits, thermal limits, as well as the number of active cores and their maximum frequency limit the clock rate that can be increased. If a processor calls for higher performance, only when the processor is below the limits will its clock increase the operating frequency to meet the required demand.

arcticx

Could someone please explain this graph? Does that mean that as time goes by, the power drops accordingly? Then what does those side notes mean? Or does it mean if working with a higher power, then it can only sustain for a short period, while working with a lower power, it can sustain longer?

Fantasy

@arcticx I think this graph means if you want to work for a longer time, your power have to drop to the according level. Otherwise, problems in side notes will occur.

For example, the "die temp" point means if you want to run at this power level longer than the time in this graph, the chip will become unreliable. To make sure the chip works correctly, you have to drop the power below this level.

aeu

@arcticx "does it mean if working with a higher power, then it can only sustain for a short period, while working with a lower power, it can sustain longer?" That is almost exactly what this graph is trying to convey. High power leads to all sorts of problems on CPUs, doubly so on mobile CPUs. In order to sustain fault-free operation, the CPU can't push over certain power levels or heat levels. Which is also why cooling is one of the most important aspects of a computer, all the way from personal computers to datacenters.