I just got my gigabyte gaming oc rtx 2080 and noticed loud coil whine while in game menu (csgo/apex/fortnite) or while playing with higher fps.
As soon as I alt tab from the game noise disappears.
Is it fixable or should I send back my gpu as soon as possible(monday)?
It's due the the very high framerate in game menus. I've experienced it in 5 out of the 9 cards I've ever own. My current card has this problem.
From my experience and anecdotal evidence from various forums, it isn't an issue and doesn't represent a faulty card.
Lowering your overclock or locking frame rate both will help. But aren't necessary. If your card has a warranty and you can cope with the whine. Keep it.
If you can't handle the sound and it concerns you too much and/or you have a short or limited warranty and are worried by the sound, return it.