Guys, the reason for this is simply because, 80C is NOT at all a harmful temperature for your card to run under load.
Companies like EVGA do stress testing that simulates 4-year conditions over a 144 hour period (see the Zotac factory tour video). These cards have to pass that test to get sold with any BIOS changes.
GPUs have historically been running at mid-80C to low-90C previously. It's only these past 2 gens the temps have come down remarkably.
Really, I wouldn't worry with the 80C temps, since the default built-in limit for Pascal is now at 83C rather than 80C for Maxwell, which signifies that Nvidia is confident with how long the card can potentially last, and the actual max thermal limit is over 90C for these cards.