If you look at OC Guru II default settings that's what it is set at. Power 100% and temp 79 degrees as the target, no idea why they choose these settings as a default point but they have.
Should not be a problem at those settings though, temp of card will depend on several things such as demand (how hard it's being pushed by the application/game) and heat dissipation qualities of your computers case design and/or fans etc.
Some people think tons of fans means extra cooling but it really depends on how well they are set-up. I like to have slightly positive pressure in my builds but you still need good amount of exhaust.
I use default settings on my G1 970 gaming, fans are fairly quiet and seem to run under 1600rpm 90% of the time and idle temp is around 22c to 28c and max temp I have seen while gaming has been 56c. I run a dual 29" ultra-wide monitor set-up which equals 5120 x 1080p.
Case is a Corsair 750D