first,the screenshot is entire window (https://www.dropbox.com/s/pselk6jsy5u3wod/Screen%20Shot%202013-09-23%20at%203.31.01.png) second,turn off the cars,even roads,doesn't help at all :s.
i run x-plane on MBPR with only 8GB ram but i always get about 28~35 FPS with "ramzzess 777"、"JAR A320neo"、"CRJ200" however the SAAB 340 kills lots of FPS and it isn't acceptable :-( the low FPS has nothing to do with the HDR setting for me