hi guys. after looking at this issue in detail, i've come to a few conclusions.
1 - running under Yosemite vs Mavericks incurs a slight performance hit for rapidly updating GUI objects. this affects Max 6 and Max 7 the same.
2 - if using jit.world with the default of @displaylink 1, there will be a fps drop when running a patch with rapidly updating GUI objects. (Max 7 only, jit.world doesn't exist in Max 6)
3 - if running on a Retina machine in hi-res mode vs lo-res, there is a significant FPS drop for any GUI activity. so anytime the patch is unlocked, window resized or scrolled, GUI object updated. affects Max 6 and Max 7 the same.
As always, if you want consistent, stable FPS from your Jitter patch, you should minimize GUI activity. if your project requires significant GUI activity (opening windows, updating GUI objects every frame, unlocking the patch during performance(?)), then you have a few options. The best is to separate your GUI patches entirely from your engine patches, and run 2 instances of Max, passing messages using udpsend/receive. a second, much simpler option is to run Max in lo-res mode (get info on the app icon, check the box next to Open in Low Resolution). a third option is to change the Max App preference for Scheduler -> Refresh Rate, to something like 200ms.
last, if using jit.world with lots of GUI activity, try disabling displaylink (@displaylink 0).
hope this helps.