From past to present who has been more efficient AMD or Nvidia?

Right now Nvidia is more efficient

Yeah Nvidia is better for power consumption...670 is probly the best though.Im getting the 7950 but it overclocks like a boss and will be faster than a 670 in most cases and even faster than 7970...

No, there is no clear cut winner in efficiency. It depends entirely on which card and what resolution. However, I'm going to have to give it to AMD because the 7750 is so ludicrously efficient as far as performance per watt it dominates most resolutions.

http://www.techpowerup.com/reviews/Zotac/GeForce_GT_640...

As you can see, the most efficient card overall was the 7750. It's the most efficient card at resolutions of 1680x1050 or lower (and tied for first at 1920x1200)

the 7870 is the most efficient card at 1920x1080 (tie with the 7750), and the 690, oddly enough, is the most efficient at 2560x1600

its an endless cycle, each one attempts to beat the other succeeds until the other makes a new line.

for instance, when amd created the HD 7k line, it was more efficient than the gtx 5xx line. then nvidia comes out with the gtx 6xx line which in general is more efficient than the hd 7xxx line on the high end(low end wise, the Radeon is still more power consumption effective, as the HD 7750 is generally better than the gtx 640)

hhhmmmmm are we going to discuss drivers?
 

Here's a recent chart:




And one from 2007: