Blinking

[Waffles]

it's probably screen tearing.

i had this problem playing on my mac with vsync disabled.
try and use a native resolution for your monitor.
try and have the game and your monitors resolution == the same thing
maybe it'd help to post your monitor specs, your graphics card, and what resolution you use in game
EDIT:and if you play with vsync, or just post all your video settings from the game