A few people have been asking how to get a little more performance or FPS out of their settings, It's going to take a little trial and error, but there are some recent graphical features that when turned off will seriously improve frame-rates for less powerful machines.
As you are on OSX, make sure you are running a 64bit java. Then in the memory options (found in options > memory settings in the first launcher) try increasing your max allocated memory to 2048.
Finding the optimal balance of quality and performance is something you'll have to tweak yourself, but for basic steps to get more FPS, try the following:
1. turn off shadows,
2. turn off normal mapping
3. turn off bloom
4. turn off procedual backgrounds (and in extreme cases, disable backgrounds completely)
5. select a lower resolution texture pack (64 being the lowest, 256 the highest)
I had written up a post for another member curious on the specific settings and their function, you can find it here;
http://starmadedock.net/threads/help-with-game-settings.1328/#post-19224
For a quick reference on the absolute highest performance settings vs highest quality settings, click the quote below.
For more FPS and less resources used, follow this rough set-up
Resolution ; 1280 x 800* (a lower res in the same native ratio as your monitor)
Fullscreen ; on
FOV; 85.0
Max Segments; 750 (or lower depending on your needs)
Shadows; OFF
Normal mapping; OFF
Procedual background; OFF
Texture pack; Pixel - 64
VBO (dependent on system / OFF)
Vertical Sync; OFF
Hi res background; OFF
Enable background; OFF
bloom; OFF
Framebuffer OFF
Atmosphere shader; OFF
2d texture compression; ON
Ingame options, turn OFF space particles and stars.
For higher visual quality!
Resolution ; Select the highest your monitor can natively support.
Fullscreen ; on
FOV; 85.0 (personal preferance)
Max Segments; Select a higher number
Shadows; ON - Ultra
Normal mapping; ON
Procedual background; ON - 4096
Texture pack; Realistic - 256
VBO (ON / dependant on system)
Vertical Sync; ON
Hi res background; n/a
Enable background; ON
Bloom; ON (personal preference)
Framebuffer ON
Atmosphere shader; ON
2d texture compression; OFF (this will kill FPS and eat memory like a monster)
Hope that helps a little.