Even though newer processors come with scaling (SpeedStep, Cool'n'Quiet), some computers have motherboards with outdated bios which do not support the feature. Thus, they run at full clock speed. Even if they do have it enabled, the processors still have minimum clock multiplier such that they can't run at much lower voltage. For CPU with scaling disabled, both 100% CPU usage and idle CPU should have the CPU running full speed. Scaling-enabled CPU, if the minimum speed is 40% of CPU capacity, the multiplier should be the same whether it's idle or it's using short of 40%. My question: does the power consumption differ between idle and non-idle in both cases?
Every operation a processor performs costs an amount of energy.
Different instructions use different amounts of energy depending on such things as how many clock cycles they take, what parts of the processor they use, etc.
Most processors have a
That is why, when you're doing intensive calculations on a computer, whether it has speedstep or not, the processor gets hotter than when it's just idling.