Doctor Rob :
normally the card will have software.. like mine (an amd one made by asus) it has an 0DB setting.. so when little to no usage the fans done spin up untill it hits about 40C (if I remember the temp correct)
Yeah sounds about right, When you first power on a system with one of these cards the fans will start to spin until it realizes its cold enough, so the fans shut off, if you open up a game and get the card under load for a bit once the temp rises then the fans kick in, and once you leave the game the fans will bring the card back down to temp and the fans will turn off again.