I have a 470, but not an EVGA. Instead, it's a reference Zotac. Mine runs at 800/1600/1950, at 1.087v. I can probably squeeze few more MHz, but I haven't bothered to tweak too much. Even with my headphones, 80% would grate on me quite a bit.
Regardless of the heat and fan, I'll be adding a second 470 in my AMD system by way of an SLI-hack. They're really good cards.