Well, maybe not a true Discovery, but:
Was using Aalto in Audiomulch just now and realized that you can really save some CPU by not using the Aalto GUI at all - just use the generic editor.
I have been obviously been experiencing an audio drag when running multiple instances of Aalto; say 10-11 total voices at ~88% cpu. Turning off the animation can save a little cpu, but dispensing with the GUI altogether makes all the difference and seems to save a substantial amount of cycles.
Not that I would ever build patches without the gorgeous interface (you can't do actual patching through this method or MIDI or host automation anyway), but this really helps when you have a thick project going and just need to make little adjustments. I know some other hosts have their own generic editors; don't use Ableton so I'm not sure about that...?
Sorry this may have been obvious to everybody but me - just wanted to share