from SnowLeopard to Mountain Lion, any diff in performance?

Well they have.
Seems there HAVE been changes to ‘Core Audio’.

However, what is known so far is that all Steinberg software products (except for Cubase LE / AI / Elements 7.0.6) are affected by an issue with the CoreAudio2ASIO component when using audio hardware in class-compliant mode which may lead to dangerous digital noise.

And what do these changes do?

Break Cubase! —go figure.
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