In modern Digital Audio Workstations (DAWs) like Pro Tools or Ableton Live, the internal processing engine often runs at 64-bit float, with experiments in 128-bit float precision for plugin development. This isn't for playback—it is for math.
There is no such thing as a "128-bit bay." Bays are physical (size in inches). Bus width is electronic (bits). They are unrelated. 128 bit bay