well I am not sure what is your experience, but the moment you turn the miner on, your GPU really stops being a nice quiet addition to the PC, it becomes a loud and hot monster with all fans on max speed. Try to do it at night, you'll see what I mean.
I have a Sapphire RX 580 8GB Limited Edition in my rig at home. It is currently mining DGB at full intensity and the fans do not run at max speed and is actually pretty quiet. I guess it depends on the algo you are mining. It stays relatively cool in the mid 70s also.
haha you may be right. At that time I played with those babys: Radeon HD7870, I had Gigabyte and MSI brands and they always went crazy 5 seconds after the miner was started