Why does it matter if its processor heavy if its isolated away from everything else? If you mean RAAT is “heavy” compared to other streaming protocols then, yes, that may impact sound quality. But Roon Core being CPU / memory bound / heavy really doesn’t matter. Just throw hardware at it and be happy.
It really doesn’t make sense to optimize the hardware of a Roon Core for low noise when the reference Roon architecture eliminates any noise from the core landing at any of the D/A stages of playback.