I get exactly the same issue as described at the top of this thread. Spotify stutters at random with breaks from a few seconds to several minutes. Web radio on MPD is generally fine and in use for most of the day. I have a simple set-up, just a Pi and some active Speakers , no DAC yet until this issue is solved. I've tried everything in this thread and others. i.e. power supply check, network check, switching-off logging in spotify, checking the cache etc. I had a ssh connection running with 'top' to monitor the pi and the processors and memory are all at a low use level and during a pause there is no significant change . I eliminated wifi and connected directly to my router via ethernet, same issue. I have switched from a Pi2 where the problem was first encountered and done a fresh build with a Pi3 [albeit with the same version of Runeaudio
RuneAudio_rpi2_rp3_0.4-beta_20160321] with a different power supply and different connection point. Same issue. Both Pi's used [different] class 10 sd cards which I checked for i/o errors before flashing. I've had issues with corrupt sd cards in the past with other Pi applications.
So I'm guessing the issue is to do with cache or I/O but it is beyond my skills and have spent many hours puzzling over it.
Spotify itself runs fine when I run the native application from a PC.
Runeaudio is such a good platform, it has transformed my listening and that's why I added a spotify subscription !
Anyway any advice or insight greatly appreciated.
Thanks