On my macbook pro retina 15 inch early 2013, when i pinch and zoom, you know zoom out to go to another tab it lags very very much, not on an external display. I have tried to change resolution to see if there was any difference, but it didn't work. And the reason i am placing this in the macbook pro section is because my dad, brother, friends etc. doesn't have the problem with their macbook air, neither do i only with my retina macbook pro 15 inch early 2013. Safari 6.1.2 beta, (it was like this before the beta too) mountain lion.