Nvidia, Asus put the clamps on GTX 590 voltage
The main cause of the problem, as we've noted, appeared to be excessive overvolting during overclocking attempts and the failure of the card's onboard power-protection circuitry to prevent the worst. We first understood this problem to be confined to an early driver set which shipped out to reviewers—and potentially to end-users, I believe—on a CD enclosed with the card. We used slightly later drivers in our testing, prior to the GTX 590's release, and the card correctly slowed down clock speeds during our too-aggressive overclocking and overvolting attempts, saving us from fiery grief.
We now understand part of the potent cocktail of smoky death may have also been a modified video BIOS shipped on Asus cards that allowed more extreme overvolting than the 1.025V peak we attempted. (Since our review unit was a reference model directly from Nvidia, we weren't able to venture much beyond that point.)