I have no idea about it , because my interest isn't in digital systems . but as i can remember , one years ago , i saw a video from MIT university . in that the professor , calculated power consumption of a pentium 4 CPU . he considered that it has at least 10^8 digital gates ( he told it is not for pentium four , because it has 20 million digital gates . ) but it was an example .
I hope this description can help you . and sorry if i can't help you as well because my field is analog .
Good luck
Goldsmith