The actual CPU power consumption should be equal to = actual input of the CPU current (A) xcpu the actual voltage (V), which is the product of the supply voltage and current. The best way is to use sophisticated power tools to test.
In addition, the general calculation of a CPU in a 24-hour day and night to run a set of programs repeatedly, and then calculate the cumulative power consumption, is very misleading test, because a high-energy CPU, can do more work at the same time.
Therefore, the actual CPU power test should be a set of statistical program combination, analog people use the computer's habit to let the computer run, such as office scenes, typical test software for Sysmark, home environment for PCMark, recommended with the latest version.
In this way, the performance of good energy-saving CPU, you can in a shorter time to complete the task, in turn into waiting, idle, dormant, deep sleep and other energy-saving state. For example, the same section of High-definition video compression, High-performance CPU can be completed in 5 minutes, poor CPU needs 10 minutes to complete. The CPU that completes the work ahead of time can do other work, or in the remaining 5 minutes at the low load running state--CPU utilization rate is low, system power consumption is small, even enter hibernate. For 10 minutes to complete the CPU, the second 5 minutes still need to let the CPU in a high load of the running state, the entire system needs to be in a relatively high load state, this shows that energy consumption can not be compared with high-performance CPU.
Using the latest technology, the latest architecture and the latest energy-saving technologies are the targets of the manufacturers, because only these new technologies can ensure the implementation of High-performance Low-power technologies. For example, from 65 nm to 45 nm, each transistor can be reduced by more than 5 times times the leakage flow, each transistor performance increased by more than 20%, driving power decreased by more than 30%. If the number of transistors is hundreds of millions of, the power savings will be very considerable.