Cubase freezes for a few seconds rotates Rainbow...

Please tell me how to get rid of this problem: I work for MAC Pro 8 core 16 gb of memory.
Starting with version Cubase 4, then 5 and now works for 6 constantly being one and the same conflict …? When Cubase is in playback mode, everything works fine, but as soon as I stop Cubase for any editing or just trying to move on to another track, Cubase freezes for a few seconds (on the monitor rotates Rainbow) and this happens all the time, it is impossible to work! :blush: Seems to have tried everything that was possible. MAC is constantly updated with the official site. Drivers for all my devices are also installed the latest. When I worked on the PC such problems did not exist. But for me to return to the PC is probably not possible (past stage in life).
If you know how to get rid of this problem, help please. :question: