both have different conclusions with the HD 6990 winning the majority of the tests. The GTX 590 only wins in a handful of titles, all of which are Nvidia biased across the board. Everything else belongs to the HD 6990. What's funny is that sometimes the GTX 590 and 580 are sandwiched in between the HD 6990 and the 6970.
Here's a couple examples of this phenomenon:
All of those examples are at 2560x1600, so it debunks your theory about the 2GB of video memory not mattering. You just need a multi-GPU solution to take advantage of that extra video memory.
Anyway, the HD 6990 is the performance king, while the GTX 590 is the quieter solutions. Regardless of your "Hairdryer" quips, the HD 6990 wears the crown.