The stuttering might not be CE related. I'm running 34c and have had slight video stuttering and really bad audio stuttering since getting the s/w. Reboot fixes it. One receiver actually went to completely muting the audio but if I hit a button that made the 'boop' error tone, it'd start the audio again with bad stuttering and slowly go back to mute.
HR20-100's, btw.
Will report this also in the 34c thread, seems it may be something that was introduced in 34x and carried over into the CE.
Well, turn the "Boop" sound OFF then !
Menu > Set Up > System Set up > Audio > Sound Effects > OFF
Jimbo