old topic but question that i'm still trying to answer: how loud is your iMac while mining? thanks in advance. have a lovely day.
I'm guessing the fans would go all the way up. Hear what that sounds like by googling and downloading smcfancontrol which lets you set preferred fan speed settings from the menubar. Just create a setting where the fans are on full. I do that for mining on Mac Pros and they're pretty loud either way, but my MacBook Pro is fairly quiet even on full. Seeing as you have a mobile GPU it might not be too bad.