Thanks for the respons, I’m running Avid Media Composer 3.1.2 with a mojo SDI on a Mac Pro 3.2 Quad Core and I have installed 18 gigs of RAM… So that should be more than sufficient! With all my other applications closed the memory usage is around 70 percent on start up… So I guess something’s wrong with my system… The question is: What is wrong? Everything else seems to be working fine…