I went back to the July 19 build of Isengard due to freezing and other issues. I am running OS X YOSEMITE, fast web,tons of memory...
Everything ran/runs perfect for me as of this build.
I am not quiet sure what you want to tell us. You went back from what version? All in all the amount of usefull information in your post nears absolute zero.
I updated to the newest version. I experienced a lot of issues after the 19 July update. I cleaned the system several times, dumped suspicious add ons, rebuilt the library, etc. I Then did a retro-install of the older build and the issues vanished. My apologies for the lack of detail. Perhaps I can retrieve the logs.
That post isn't even better. Maybe you should read the big fat sticky post in this forum on how to report a problem in a usefull manner.