Browsing library very slow (Sonos/raspberry)

[Optira]

I already posted this issue on the beta-thread. Unfortunately it's still present:
I've a big problem with browsing the library with my Sonos-app (Android) and Windows client (Raspberry Pi 2 server). It's very very slow. I think it has something to do with the "new feature" that now the "artist-picture" are shown as icon (from last-fm?).
Currently the app is nearly unusable (~ 45 sec. for ~260 folders everytime when I go to "Browse library").

[300Baud]

Hi - did you find any solution? I have a very similar problem running subsonic on a Netgear ReadyNAS RN102