Can Logic Studio 9 utilize all 12 cores of my tricked out Mac Pro?
It's got two Intel Xeon X5670 processors in it.
Logic Studio uses multicore when the action permits. Certain plugins won’t be optimized for Multicore and therefore will run on one core. When you bounce and play real-time, it will definitely use multicore. The more, the merrier.
You can grab a copy of any CPU meter, for example iStats and see for yourself.