So I was using Cubase 7 in Snow Leopard which was fine apart from some annoying bugs so upgraded today to Mountain Lion. I open a basic project with only 20 tracks that was running about 80% performance in Snow Leopard this morning but in Mountain Lion it goes straight into the red and wont play.
I thought I was going to see a performance improvement not a set back like this, how can this be?
This happened to me two or three times on PC since C7 release, that small project pushed performance meter into red, although it shouldn’t. What helped was closing the project, loading another project, closing it, and then reloading the first project again. It was like something got stucked, and loading another project un-stuck it. I have no other way describing it. 
Cubase seems to be getting more and more analog-like, in a way that maybe soon some kicking the box with a foot will help it run again after getting stuck…
Try turning off ASIO Guard and see if that helps.
Aloha C
IMHO even with out using Cubase, ML will use more cpu juice than SL.
I like sonicstate’s suggestion.
It’s such a ‘computer’ answer.
Also, try increasing your buffer size a notch or two.
HTH
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