That's fine. G92 chips can handle 80c without issue. My 8800GT hits 82c with the default heatsink and fan profile and has been running great for over two years straight.
Ok, that's a little reassuring to know that i still have some headroom.
tweaked the shaders to 1500 and mem to 1000 now. I wanted to see how much further i could get the core, but furmark had an initial hiccup and then a crash when i hit about 730-740, so I'll just leave it at 700.
At those settings, temps zigzag 71-72 C, so I'm happy with that.