I tried 128 buffer on my Mac Pro ( 4 core, 3.7 Ghz) -Playback works fine. Cpu on PC reaching 56% at max. Few times, max spikes on few cores on the Mac Pro. -Surprisingly recording a new track while the template plays back, works fine. -I had to reduce the 4 Strings instruments from 4 to 3 mics due to disk streaming overload at the climate on the composition (quite annoying half of the strings players suddenly goes for coffee brack), which I dont understand. Is 5 string instruments x 3 mics + 4 string instruments x 4 mic with Spitfire symphonic string Performance Legato to much for a Pci ssd (1700 Mb/s)?