Banshee (and Rhythmbox) plays an audio CD for exactly 16 s, freezes for about 12 s, runs ahead, freezes again, etc. 

These commands produce choppy playback:
   gst-launch cdparanoiasrc mode=1 ! audioconvert ! audioresample ! alsasink
Adjusting element properties such as blocksize, read-speed, and paranoia-mode does not help.
  gst-launch playbin uri=cdda://
Fiddling with the playbin element properties such as "delay", "queue-size", "queue-threshold", and "queue-min-threshold" can improve things somewhat, but does not eliminate the problem.  

This command produces normal playback:
   gst-launch cdiocddasrc mode=1 ! audioconvert ! audioresample ! alsasink

Running Banshee via a terminal with --debug set reveals nothing striking during choppy audio CD playback.  Top does not reveal huge cpu usage by Banshee or related processes.  Other features of Banshee seem to work fine. IBM Thinkpad 600E (as well as a Dell Inspiron 7500), Fedora 10, kernel 2.6.27.25-170.2.72.fc10.i686, banshee-1.4.2-4.fc10.i386, gstreamer-0.10.21-2.fc10.i386, pulseaudio removed, ALSA selected as the preferred playback method.  Audio CDs play fine under Grip. Rhythmbox used to work fine on this machine in the Fedora 8 era. /var/log/messages reveals nothing.  Audio CD playback by Banshee is normal when played through an external USB DVD drive rather than the Thinkpad's internal CD drive.  Per the Banshee forum, Banshee uses playbin to play audio CDs.  

Almost as an aside, simply running cdparanoia by itself in a terminal smoothly rips a CD much faster than playback speed.