I agree with much of what you wrote. PG Music uses a proprietary process for RealTracks so we just cannot know some of it. I can guess, based on observation, that what’s going on when playing back a BIAB song is very different from any other audio program. The CPU demands are very high. Rendering appears to be two steps: the first is the same processing as playback. The second is saving to disk. Both benefit from faster storage like using a SSD, but only generating makes heavy use of the CPU.


BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.