by PeteB » 28 Mar 2016, 04:32
You could transfer some files to the SD card to reduce the dependence on USB.
Change some of the RuneAudio settings, like buffer size, etc. (I doubled my default buffer settings in MPD).
You could also check the CPU load at the Pi, it should only be a few %, and if you see it spiking above, say 10~12%, something else may be slowing the Pi down. Memory too, not just CPU load.
You never said what kind of files you are playing, you could compare 44.1/16 v. 96/24 and see if one clock is better than the other, MP3 v. FLAC, etc.
Anything to narrow it down a bit.
Good luck, and I hope you get this sorted!