Try to enable "Radeon Chill" in drivers and also please read the temps from the driver, when the card is noisy. I assume that your cooler threshold will be around 60°C?
Gaming >> Global Settings >> Chill
PS Radeon Chill is not supported on all games.
Profiles should apply automatically for you, no need to worry. Mission is "easy" you need to keep you temperature below card "Silent threshold", when in full load. Real safe values are probably 65°- 70°C, depends on the piece.
Or/And you will need to add additional cooler in the bottom part of your computer, in-slot ones might cut it, take a look on
them. This
one looks better.
Root of this problem is, that you don't have sufficient airflow in the bottom part of your PC. Where the upper part is perhaps saved by that one system cooler.
Where is your PC placed, does it have at least 7-10cm from the wall?
Also check if you card is having hw switch Silent/OC, for older edition it looked like this and it still should been here:
As for undervolting Reddit says:
I have the XFX RX 580 8GB so pretty much the same card. Not got the info in front of me but I believe it's 0.836 for the core and 0.9 for the memory. Haven't tried going lower as I've read this is the lowest it goes without instability.