Using 9.0.2 with Kontakt and Symphobia & True Strike 2, are there any advantages of using several sounds within one instrument strip (multi timbral) or using a new instrument object for each new sound? Is it more memory efficient to do the former, for instance?
Try this: Double click on the System Performance meter (cpu, hd) in the Transport.
Load one instance of Kontakt with say 16 instruments to play back 16 MIDI parts in the Arrange. What does the performance meter show: balanced distribution of load on cores? Or one core maxed out?
Now try loading 16 ( or whatever number you choose to work with ) instances of Kontakt with only one instrument per instance. What does the performance meter show you?
Seeing this for yourself will make a greater impression of the better approach.
Loading 4 instances of Kontakt with 4 instruments each seems to have the same beneficial balanced load on cores.
So it's a balancing act.
The EXS 24 is a one-instrument-per-track-type of software instrument.
As of Cubase 5? Instrument tracks were introduced- (one instrument per track) vs the prior and still existing VST Rack which is for loading say a multi-timbral Kontakt.
It is a good idea if you load the Kontakt as a single Multi Output instance and route the audio output of each Kontact internal instrument to different Logic Aux objects.
This way you will optimize the multi-core performance.
Have a look at this Tips for balancing multi-core performance.