choppy playback?

Spoiler alert: I’m a newbie.
Anyway. The playhead seems to be going in a choppy and unsmooth manner. Automation sounds affected by this, as if the fade has a an interval of 5db. Any ideas?

macbook pro
2,3 GHz Intel Core i7
16 GB 1333 MHz DDR3
Intel HD Graphics 3000 512 MB
OS X 10.9.1