Oh wrd, aggressively clocked, the 5970 is still king of the MH/$ title. I was thinking more about how I run my 5970 during the day, at 550 MH/s (887mv, 605/200MHz). So comparing that to a theoretical 7990 doing 1.1GH/s, the MH/$ are more similar, especially given the current market price of a new 5970.
I gotcha although I doubt many people will be dropping $850 to undervolt the 7990. Undervolting IMHO makes sense to extend the life of old cards.
I run my 5970s flat out. In a couple years if the network is more efficient (lower price /difficulty) rather than turn them off I will undervolt them and eeke the last bit of profit out of them.
