Interesting thoughts with the voltage changes. If I run in to issues at some point I might look into that.
But as I said, literally no noise issues with my MacBook Pro Core 2 Duo. And I don't think that our original poster is going to be pushing his machine even as hard as I do. I think he said 8 to 16 tracks, not heavy on the plug-ins. As I said, for me it's usually up to a couple of dozen audio tracks (nothing frozen), several midi tracks of different software instruments, plenty of effects, Reason 3 through ReWire, and Amplitube 2 or GearBox all at the same time, and the thing is hardly even out of first gear. Not that I would, but I could probably run Windows in Parallels at the same time as all that, while simultaneously surfing the web, composing a Word document, IM-ing people, and have Mail open. I don't know, maybe then my fan would come on?
I do not mean to contradict you in any way Tui, that's just my experience with it.

Do you run hundreds of instances of PlatinumVerb or SpaceDesigner at once? Or maybe you have some really CPU-intensive 3rd-party plugs?
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2.33 GHz MBP C2D
Logic & Reason, with as much divine inspiration as I can muster.
"A melody is like a pretty girl. Who cares if it's the dumbest in the world? It's all about the way that it unfurls..." -MF