Do one frame in 24. This is very slow and useful only for background computations or playing music without interactive graphics.

Do one frame in 12. This is quite slow.

Do every sixed frame.

Do every fourth frame.

Do every third frame.

Do every other frame (recommended if you don't like Auto).

Do every frame.

Automatically adjust the frame rate to the value that keeps the Mac CPU loaded less than 90%. (recommended)