Asking around we learned that the weird clock of 612 MHz was not the only thing the company changed. Namely, they changed the bios and let people use 1.2V (default is 0.9) which is way to much for the card. It ultimately results in TDP going up to 550W. As you can imagine, this is way to much for the card to handle and the power parts give up, eg. burn.
Nvidia wasn't tightlipped as the company got back to us with a following statement:
"NVIDIA's reference GTX 590 VBIOS on the production boards has not changed, and we have not provided a new VBIOS to AICs or end users for GTX 590. The original GTX 590 VBIOS that NVIDIA shipped is good for customers to use and we stand fully behind the reliability of the hardware with that VBIOS.
We did hear of one AIC partner who issued a custom VBIOS update specific to their board and we are checking in with them on the details of this."
We will hear more tomorrow but the new driver doesn’t let the card to draw insane amounts of power such as 550W, as this will clearly kill any possible card we know of. New driver prevents it despite the bios tweaks.
So far out card didn’t catch fire, and it works well even overclocked. We are not aware of any issue with highest clocked TGT cards either. Let's see what tomorrow brings."