I can test on 10.10 DP4 for you but I don't have an AMD GFX card and my Nvidia 9400M barely runs it on Windows, I'm guessing it doesn't stand a snowballs chance in hell in OS X. I don't suppose you have an inbuilt feature for turning on an FPS count on OS X?
I need to check, but I might have a spare App Store code for Yosemite Developer Preview (I have iOS and Mac developer accounts) - no turns out they don't give you the spare key.
