I dont think getting GIT will give you better results than a GIT-Snapshot ! may be 5 fps more thus that wont be enough to fly decently. When you get 1 FPS where do you fly ?
This is important, i am Mac user too, having 1.9.1, 2.0 and GIT snapshot, the FPS are always pretty good even if its 5-10 below the 2.0 version with some exception . For example when facing the KSFO terminal my FPS drop to 1 !! when looking at a C172 same thing occurs , also with some other models. I will suggest you to remove some of the useless aircraft that you have in your GIT folder (like C172, F4U and few others you dont fly often !). Keep the best ones and the one for which you need to have GIT version. Avoid KSFO ant its close area. Remove some of the features like Urban Shaders (deactivate it) , Water Shaders (except when necessary, ie snapshot, movies...) and so on. You should get a better much better FPS.
Cant remember what kind of Mac you have nor what Graphic card, let me know and i will compare to mine (but i think your imac is superior so no reason for GIT to give you 1 FPS only).
Pat (Pat 70 on the forum...) sometimes as Pat2 on the Laptop
Member of the FG Rotor Flying Club http://fgrc.tk/