How common is coil whine?



Is it worth the RMA process if it whines from 240FPS and up?
 

No, coil whine won't affect the cards performance and is not really a defect, not a damaging one anyway, you'll only really get 240 fps in low end games/menus so you shouldn't hear it that often. You could use MSI Afterburner to limit the fps to 144 if that would be a better option for you?