I hit 90C with my 275, the stock cooler is not very good.
yh its not since the card is powefull nvidia should provide big cards with bigger fans
They only need to keep the card at a safe temperature, not at a temperature that allows you to overclock the card like crazy. They also assume most people don't have 110F/43C days throughout the year
80C? don't worry about it. Video cards run hot. and 80C is totally normal. Temps always vary depending on your ambient temps. Heck my card idles at 35-37C and the way my studio is setup my desk is on the other end of my kitchen. When I cook heavily the cards idles at 45C because the ambient temps go way up.