My late 2013 imac has a i7 3.5 quad, NVIDIA GTX 780M 4GB, and 32 GB ram I have now done a direct comparison, and Windows via Boot Camp on a mac should be standard advice, and a relatively easy choice for those running Dolphin. There weren't any subject lines that were searchable specifically for this question.
This same advice and information is buried in comments of several other threads - with lazy statements such as OS X Sux, but I had a hard time finding definitive advice searching for it via thread subjects. I started this thread after quite a bit of searching - and personal testing on my own machine. It takes merely a few moments to reboot your machine into Windows to run Dolphin at much-improved frame rates and resolutions.
It makes a huge difference, particularly with certain games. To those of you with respectable specs on their Mac hardware wondering why they can't run Dolphin with good performance: Install Windows via Boot Camp.
