Originally Posted by Sazar
I wonder if AMD will respond with a dual-5870 cross-fire card to counter.
Perhaps I'm misunderstanding you, but that's what the 5970 is. The GPUs in the 5970 and the 5870 are the same. They're simply clocked down in 5970 to slide in under PCI-e power requirements. Doing this allows the card to register at 296w which is its peak load.
PCI-e spec is 300w for a single card, so neither Nvidia nor ATI can exceed that. This proves a real problem for Nvidia since Fermi is so power-hungry in single GPU form. GTX470 seems to fall short of 5870 in most of the benches, yet it still consumes ~30w more than 5870. So even if they could stack two of these on a PCB (which they can't without really gimping the chip,) chances are it still wouldn't win out over 5970 which uses two 5870 GPUs.