no no no
not overclocking the "shit out of them"
Im talking clocks at 950/180 - with 440mhash no big deal at all. the 5870 is a superior mining card to the 7000 series we have seen so far
the fact of the matter is AMD is NOT designing their cards with mining in mind and thats a fact we just have to accept.
a 7000 series mining farm will NEVER be profitable unless of course you get free electricity or some other bizarre circumstance
If you count the 5870 at 950mhz then you should count the 7970 at 1125mhz (at which it should do close to ~500mhash judging by the numbers). And that's with an unoptimized miner for a barely available card that was released, like, five days ago, smack in between christmas and new years eve celebration seasons.
Assuming that, with an optimized miner, the 7970 can do the same speed PER SHADER as the 5870, then the card could do ~520mhash on stock and ~620mhash overclocked. This is without looking into further enhancements made possible by the new architecture itself, if there are any.