[SOLVED] Stutter while playing music

[Eruurk]

Software
XBian version: STABLE - XBIAN 20150304-2
XBMC/Kodi version: Kodi 14.2 RC1
Overclock settings: XBian defaults (840 MHz)

Hardware
Device type and model (e.g. Raspberry Pi Model A/B 256/512 MB, CuBox-i i4Pro, ...): RPi Model B 512 MB
Power supply rating: Nokia Phone power supply 1.3 A
SD card size and make/type: Sandisk Ultra 8 GB Class 10 (SD Card)
Network (Ethernet or wireless): Ethernet 100 MB (My Ethernet switch can provide speed up to 1 GBps)
Connected devices (TV, USB, network storage, ...): NAS Synology DS213J over NFS - TV Samsung (HDMI)

My XBian /etc/fstab

Terminal

192.168.0.10:/volume1/music /media/nfs-music nfs udp,noatime,rsize=32768,wsize=32768,nolock,nfsvers=3 0 0
192.168.0.10:/volume1/video/films /media/nfs-films nfs udp,noatime,rsize=32768,wsize=32768,nolock,nfsvers=3 0 0
192.168.0.10:/volume1/video/series /media/nfs-series nfs udp,noatime,rsize=32768,wsize=32768,nolock,nfsvers=3 0 0
none /run/lock tmpfs noauto 0 0
none /run/shm tmpfs noauto 0 0
none /run/user tmpfs noauto 0 0
# UNCONFIGURED FSTAB FOR BASE SYSTEM
/dev/root /home xbian subvol=home/@,noatime,nobootwait 0 0
/dev/root /lib/modules xbian subvol=modules/@,noatime,nobootwait 0 0
/dev/root / xbian noatime,nobootwait 0 0
/dev/mmcblk0p1 /boot xbian rw,nobootwait 0 1

#######

Hi,
I noticed that I can hear stutter while playing music (FLAC or MP3) during 1 or 2 seconds max. It seems to be random while songs are playing.
I found in the log file that each time I hear stutter, the following line appears

Terminal

14:42:46 T:3024557072 NOTICE: CAESinkPi:AddPackets Underrun (delay:0.00 frames:2205)
14:45:30 T:2883580944 NOTICE: Previous line repeats 56 times.

If the screen saver is lauched (after 3 minutes without human activity), the line appears too

Terminal

14:45:30 T:2883580944 NOTICE: XBian : on saver
14:45:30 T:3024557072 NOTICE: CAESinkPi:AddPackets Underrun (delay:0.00 frames:2205)

I tried to change values of NFS mount share without success (like rsize and wsize).
I totally deleted .kodi directory, and the system created a new one. No data has been restored from previous to check if the problem was into the profile: no success

Thank you for your help.

Eruurk