[EDIT]hmmm.....whats going on at AMD? (and history of 3Dfx Rampage)

[ocre]

I'd beg to differ with you, though - 28nm cards with custom cooling seemed to show lower power consumption figures than those with stock cooling.  Just look at the HD 280X or 7970 GHz Edition compared to the 7970.  Most review sites received custom-cooled cards for review, which ran at far lower temperatures along with lower noise, and the power consumption was also somewhat lower in order to compare better against GTX 680/770.  

While it is true that the 7970ghz used more power than the original 7970 and the ghz ran a few degrees hotter but you seem to have completely ignored (or dont know) the other critical factors which are well known to directly impact power consumption.

1) voltage
2) clock speed.

Amd pushed up both the voltage and clock speed on the ghz. It's well documented that simply undervolting GCN reduces consumption and some claim to have dramatic results. While all chips have respond the same way, more volts equals more power consumption. It appears reasonable to assume GCN is sensitive to small increases in voltage.

As for the other gpu you bring up, it's also a common bet that as time goes by, the process, chips, and nodes mature. The later gtx 480s for example, they were greatly improved from the first batches.

All these things make it impossible to conclude, it's flawed bad. The only accurate way is to have a gpu, run it at 80c while measuring the wattage then take the same setup, same clocks, same voltages, same card and cool it to 70 and measure the difference. I don't think it will be that big

You also must remember, these things are not linear...it's on a curve