CPU Power Consumption Calculator is a very simple and handy application aimed at overclockers with an intention of helping them estimate the power consumption of their overclocked processor or processors.
How to Use the CPU Power Calculator v1.0
Picture 1 illustrates the input fields of the application which all have to be filled in.
1. <Stock CPU speed>. This is the highest operating speed of a CPU under 100% load without any system modifications. To obtain this value, check the CPU-Z “Core Speed” reading while running something really heavy on a CPU, like LinX, Intel Burn Test, Prime95 or something else you are well aware puts a CPU under 100% load. The MHz input example is shown by #1 in picture 1, however, GHz input is supported, too.
2.<Stock CPU voltage>. This is the voltage supplied to a processor under heavy load without any system modifications. The easiest way of finding the stock voltage of a processor is checking the CPU-Z “Core Voltage” reading while running something really heavy on a CPU, like LinX, Intel Burn Test, Prime95 or something else you are well aware makes a CPU run at full voltage. Voltage value should be entered in the format as denoted by #2 in picture 1. Either a comma or a dot may be used as a separator.
3.<Stock TDP rating>. This is the maximum power dissipation value of a CPU im watts under maximum load without any system modifications. To get this value, simply head over to www.cpu-world.com website, find your CPU listed there and then locate its “Thermal Design Power” number. Input example is shown by #3 in picture 1.
4.<Overclocked CPU speed>. If for some unearthly reason you have forgotten what your overclock actually is, just follow the first step.
5.<Overclocked CPU voltage>. The same exact approach as discussed in step two is advisable.
6. Once the data mention above has been entered, the power consumption estimation will appear as shown by #6 in picture 1.
Next, let’s take a look at the real life power consumption figures of the Intel Core i7 980X processor. Fully loaded, the processor runs at 3.46GHz across all cores which are fed by 1.241 volts as shown in picture 2. The total power consumption of the Core i7 980X system during idle was measured at 139 watts using a multimeter. With Prime95 fired up, the multimeter was reading 272 watts. If we do simple math and subtract 272W from 139W, we get 133W for the CPU power usage, which is very close the advertised 130W.
The processor in question was overclocked to 4.4GHz on all cores. To achieve this task, the voltage of 1.416v was applied (picture 3). A 360W total power draw was measured. Having figured out the aforementioned power draw related figures, we can now find out the approximate power consumption number of this i7 980X by subtracting 360W from 139W, which equals 221W. Remember, 139W figure represents the total power draw of the system with the stock CPU at idle.
If you pay heed to the #6 figure of picture 1, you’ll see the CPU Power Consumption Calculator was able to maintain 97% accuracy in comparison to the real-life figure of 221W, which is pretty good. The observed error can be explained through not taking the leakage power into consideration as it’s difficult to model.