So I've been messing around with Dolphin a little bit today. The current release runs really nicely on my desktop but I heard the older versions were a lot faster so I've been checking some of them out.
Turns out they weren't joking.
Metroid Prime is running at nearly full speed on my Macbook Air. :O
I'm using r7722 on the Mac so try a version around there. I'm getting around 50-60 fps with it. The newer versions (3.0 onwards) are barely running at 20fps on the exact same computer, go figure.
http://www.dolphin-emulator.com/download.html?list=22