Originally Posted by Rollo
The 11W and 15W differences you linked are pretty irrelevant given the power consumption of these cards. No one will be saying,"I'm environmentally conscious, so I use a 350W 6990 instead of a 365W 590!". (at least no one who doesn't want to look foolish)
The only factor that matters in the power/heat/noise category is noise, because it's the only metric with a significant difference. (most reviews I saw had the 6990 50-100% louder)
The fact of the matter is the GTX 590 uses more power than the HD 6990. The reason I posted this is because someone said the HD 6990 uses more power, which is clearly not true.