Garritan Instant Orchestra (IO) was made with new and different samples than Garritan Personal Orchestra (GPO4 previously, GPO 5 was released post-Instant Orchestra). Instant Orchestra contains pre-packaged groups of instruments, combined sections (brass, strings, and winds), orchestral effects, and mood-based presets; whereas, GPO 4 and GPO 5 contain sounds for individual solo instruments, allowing users to build their own string, brass or woodwind sections. IO contains pre-defined groups of instruments in each sound, and no solo instruments.


Garritan Instant Orchestra is geared more toward quick and efficient audio production, with GPO 4 and GPO 5 designed for more fine-tuned control with notation programs or sequencing software.