Apple Logic Pro 7 User Manual

    ESB TDM and EXS24 TDM

EXS24 samples reside in the computers RAM (although large samples can also be 
streamed from hard disk, in realtime). Should any Instruments loaded into multiple 
EXS24 instances use the same samples, RAM usage is unaffected. This intelligent 
memory management ensures that any given sample is only loaded once into memory. 
This allows the use of the same sound program (sampler instrument) or some/all of the 
same samples in several EXS24 instances, with minimal impact on system resources.

Another point to bear in mind is that the EXS24’s sound generation engine is calculated 
by the computer, and will therefore cause some CPU load. If you attempt to 
simultaneously run numerous polyphonic EXS24 instances, you may notice a degree of 
computer slowdown. 

As an expected performance example:  a Macintosh G4/800 (with sufficient RAM), 
running 24 sampler instances, and using a combined 64 voices of polyphony should 
not pose a problem.

ESB TDM

The ESB TDM allows the outputs of Logic’s DTDM “native” audio engine to be routed 
into the inputs of the TDM mixer. This is done via Digidesign StreamManager. You can 
activate the DTDM driver via the Audio > Audio Hardware & Drivers menu.