When i was aircooling mine mine was around 51c idle and 70 load and that was with the bios volt mod and OC to 465/1.25 Now im water cooled i idle on average 38c and full load never goes above 50c I can also overclock higher . Highest i got it was 495/1.22
well i run at about 45-50c idle, and no more than 75c full load and i mean playing far cry and doom3 for hours
You should have 0 issues with your card maintaining 80C under full load. I trust you are using the temperature logging in rivatuner to get your temp measurements, because tabbing out of a game to see what the nvidia driver window says isn't that accurate.