[citation][nom]siliconchampion[/nom]It seems to me like power consumption on this card would be fairly astronomical. Since one 580 uses something over 250 watts, what types of concessions are they going to make to clock rates and core counts to fit within the allowable wattage for the PCI-E standard?[/citation]
Most likely decrease clock rates. Correct me if I'm wrong: since clock rates increase heat exponentially, lowering it a bit might have a good impact on heat dissipation.
So instead of seeing 1gpu@772mhz, we might see 2gpus@675mhz, or something like that.
I'm a bit skeptical about this gtx590. nVidia does have higher power drawn on their gpus, and that's the limiting factor here. Maybe even with 2 gtx580 it won't be able to beat HD6990, cause they had to be downclocked so hard. And even if it does beat the 6990, I bet it's going to cost a lot more.