Yes.
Yes, there is a buffer on system disc but for full track. See screenshots:
first track
next track
Track loading in max internet speed (60 Mb/s for my internet plan) immediately after the start of the track:
(I apologize for the Russian interface of the monitoring program, no English)
The buffer is most likely on the system disk, because the hard disk is accessed during the buffer filling (the hard disk activity indicator works, however as with the further playback of the track). If this is the case, is it not better to use RAM buffer? @brian ?