On Thursday, February 4, 2010, Emanuel Rumpf wrote:
  Has anyone ever played a plugin in realtime ( live
)...
 ...and I don't mean a one-finger melody, but a mutli-polyphonic piano
 piece, eventually with sustain held down, which resulted in about 20 to 40
 simultaneusly processed voices.
 I just realized, that I've never been able to do that. Neither almost.
 Frustration.
 But on my digital piano, I can to it.
 That thing is some years old and definitely doesn't have 2 x 2 GHz
 processors available. 
A musical instrument is something designed and built for playing music. You
can certainly produce sounds with a computer, but a general purpose computer
is best suited for computing... anything.
  Anyway.
 The answer so far has been: That system is more dedicated, thus it
 can, while my PC cannot.
 The conclusion:
 I'm working with a wrong system !  -  It doesn't allow me to work the
 way I intend.
 Damn. What did I buy this system for ? I don't need those 2 x 2GHz for
 word processing - right ??
 This makes me wonder:
 Which one is the system for my requirements ?
 Which one is able to make some softsynths / samplers
 process 30 voices in less than 9 milliseconds ?
 Could my system be extended or modified in order to suit ?
 How then ?
 We have dedicated hardware for graphics, why not for audio ? 
Exactly. Better start with a good audio interface. You should not expect to
convert a laptop with a cheap integrated Intel HDA sound interface into a
good musical instrument.
Regards,
Pedro