And here's where pushing two power-hungry Tahiti GPUs as far as they'll go comes back to bite you. If our power consumption benchmarks were Star Wars, then Asus' Ares II is the evil Emperor. We're not sure if the company's engineers were paying attention to the PCI Express electromechanical specification or what. But the card goes well over the 525 W that one 16-lane slot and three eight-pin connectors are rated for. It comes close to doubling what a GeForce GTX 690 uses, and exceeds HIS' worst-case measurement by more than 50 W.
Bear in mind that those are card-only numbers; they aren't representative of the entire system. While we'll acknowledge that Asus built-in some headroom for overclocking, and suggest that you can bring power consumption down a bit by undervolting the Ares' GPUs, these are the numbers you'll see out of the box. Brutal.