Kubuntu Natty, latest Amarok, phonon backend on Intel Core 2 Duo 3G RAM, 2T Western Digital HD.

Nothing else running.

Regular songs, e.g. Billy Joel album, play without issue, but a long cut of Beethoven/Backhaus stutters as though the hard drive is not feeding fast enough. Don't see how that could be.

Is there a buffer setting somewhere that I've overlooked?

Please try alternative Phonon backends and see if the problem persists. GStreamer and VLC are the currently maintained backends; Natty defaults to GStreamer, so install VLC (phonon-backend-vlc) and test with that. (Change backend in settings > configure Amarok > playback > configure Phonon > backend)

What version of KDE do you have installed? If you are trying Neon or other trunk packages, this could be caused by a temporary regression in Phonon (which led to it not detecting Pulseaudio on compilation). With the VLC backend this leads to extreme stuttering.

Unfortunately I'm on the road in Thailand and Laos -- back soon to Singapore, and can try a long track then. We'll see if the vlc-phonon backend fixes it.

Now if I can figure out how to play ape files rather than converting them...