HiFiBerry DAC+ results in stuttering

Hi all,

As a real audiophile that wanted some sound in my bedroom, to play while reading, i find the Volumio project very interesting. In my living room, I have a very nice set based on a Cyrus streamer.

The volumio running on a Pi B+, combined with a HifiBerry DAC+ looked like a great solution for the bedroom.
Now I have the kit working, and the NAS attached, the sound is quite good.

But I do experience quite some stutters. In 16bit/44.1kHz it is all quite acceptable. But on higher bitrates things go south. 24bit/192kHz is unplayable.

I have volumio 1.51 installed.

Any suggestions on how to solve?