Hello! I've an iMac 21.5 Late 2012 (OS X 10.11.1) and I use Logic Pro 9 and X to make music. I usually work with heavy projects. Logic Pro X works well (yes, it sometimes need to exit, or it appear Overload Error when playback is on) but in Logic Pro 9 the situation is really bad...when I open big projects the program usually crash after 5' or less time and return this error "Logic Pro has unexpected quit. The current project has been saved as [...]". Plugin often crash and they aren't loaded on the sistem ("Failed to load plugin" error), and else the arrange view lags a lot, I mean when i move the mouse and the tracks of the project, graphic interface has bugs! I tried to freeze track to save RAM and CPU. the program works better but in every case it crash after 5-10'... I have already put the Buffer Size in 1024 ms dimension... Why Logic 9 works bad? Because of the memory (2x4 DDR3 1600 mhz)? Or because of hard disk (5400-rpm)? Or because of software? Thanks a lot guy!