Estimate approximate power consumption of a PC

Question

I wanted to know whether we can approximate the power consumption of the PC if we have
1> sum of peak power consumption of all PC components in Watts (P)
2> machine uptime (T)
3> Avg CPU usage (Pcpu - a number between 0 and 1)
4> Power supply power factor (PF - a number between 0 and 1)

I have formulated this equation. Please verify if it makes sense, or if it needs any corrections.

Total power consumed = (P x T x Pcpu) / PF

Any other suggestions are welcome. I just want to approximate it.

Thanks,
Samrat Patil

Answer 1

Will this site from asus do the trick?

Asus Power Supply Calculator

Answer 2

See How much electricity do computers use? or see Why Estimate When You Can Measure?

Answer 3

Your formula is assuming that power consumption is directly proportional to the CPU usage. I think this is a bad assumption, though don't know what the correct answer is. But basically there will be lots of (or at least some) other "overhead" power being drawn, even when the CPU is idling.

I think it would be something more like (P x T x (Overhead + PowerCPU x Pcpu) / PF.

Though I'm not sure that Power Factor should actually be considered.