I have been testing my plugin in Live on OS 10.5, as this is my main VST host, and it can also host Audio Units. I tend to test VST, as it doesn’t require a restart of the host (for some reason, I always have to restart Live/GarageBand/Logic in order to make it accept my changes).
Anyway, I just noticed that my plugin takes around 100% of the CPU when running as an Audio Unit in Live or GarageBand (on my late 2006 MacBook Pro). The same code runs at about 1% as a VST. Not good.
A truly weird thing I noticed: The CPU only goes up to astronomical levels in GarageBand when I am actively viewing the GUI. As the GUI does not come up for Audio Units by default in GarageBand, the plugin first instantiates with a nice low CPU.
Any idea what is going on here? I am working with the almost-tip (I updated about a week ago). Have other people encountered this with their plugins?