Pulseaudio has had a long history of being poorly handling certain audio chipset drivers, I'm afraid. You may be able to solve your problem by adjusting the the driver parameters in the file: /etc/pulse/default.pa. You will need to have administrator permission to do this. Be sure to make a backup copy of the file before you make changes, just in case.
Edit the line: load-module module-udev-detect and add "tsched=0" so it will be: load-module module-udev-detect tsched=0 Save it, and then preferably reboot, just to be on the safe side. Don't worry, this parameter should be perfectly safe to use. It will force PulseAudio try to not bulldoze over the sound driver's timing by forcing the scheduler to 0. As a last resort to fix problems with PA, I've backported a newer version from Sid to Debian Stable, but I don't recommend that unless you really and fully understand what you are getting into. It can cause problems.
