Just a few days ago, Pro Tools popped up the annoying "A CPU Overload Has Occurred" dialog box while I was working on a mix. Mid-2015 rMBP, 2.5 GHz.
It was a pretty simple session, too - nothing that breaks any rules, like reverbs on inserts. 12 or so tracks and three stereo effects (on their own busses).
I'm amazed every day at how much capability my MBP puts into my hands, but it is not without limitations. To say it's sufficient for any pro audio workflow is a bit of a stretch.