I recently killed My GTX 570 too. Voltage was set to 1.05. I had tried running a game of Nexuiz before i even got into the game my system reset tried again and 2 more times reset, then followed by a burning smell. No pictures yet since im at work.
I took the sinks off and saw a fried Mosfet on the VR. I noticed someone else here bought replacement part from digikey. I did the same thing but haven't received them yet. I ordered this part here
After doing more searching I found a bteer replacement part and suggest replacing all fets with this instead.
This FET has better current handling and a lower on resistance.
Ive also figured out which part is used for driving them. There are 4 gate drive IC's next to the fets which could have also gone bad. They are IR3537.
If you replace one fet you'll need to replace the one next to it as well at a minimum. When one fails it shorts out the other most likely killing them both. It's even possible that since the all the VR sections are paralleled they could all be dead. hopefully not.
Also removal of these fets is very difficult. I tried using a hot air pencil with no luck and got two removed using two fat soldering irons simultaneously on one fet. I had huge half inch tips on them. Obviously someone with the proper rework station might have better luck. I plan on posting my results once I get my parts in. I did end up messing up the pads on one FET but I think it will still be possible to fix.