Unfortunately I haven't stressed this setup under
real-time conditions
yet. But so far I have had no real issues when recording band
repetitions or when trying to compose tracks. I can't go lower than
128/48000*3 but that's mainly because this setup isn't tuned for
real-time work.
8 ms is much better, then what I can do with my non-encrypted desktop
PC and a RME audio card. IOW I guess it's important to mention how many
audio/MIDI tracks are read/write during a session. "128/48000*3" without
knowing what you exactly did, is a vague information.