Not sure if anyone is lurking with buffering / playback issues. I have had substantial problems with high bitrate files since 4.0.2.
Initially did a reinstall without any success, but eventually tried it again after getting frustrated and not finding anyone else on the forum with these issues.
2nd time did the trick and I’m now getting flawless playback with 20+ gb files over ethernet. Long story short - if you’re having playback issues w the current version (or 4.1 beta), try a reinstall!