In regards to part 2, have you tried either using the -rt flag for PD (may require sudo or root, depending on your config) or using JACK? The first solution (realtime) often fixes many click problems. Otherwise, you might also make sure your video card is properly set up. Type "glxinfo" and look for the line:
direct rendering: Yes
to see if OpenGL is properly set up for your graphics card.
and -blocksize (up and down) and I still get frequent audio pops. 3) I haven't tried using 2 pds in parallel one for sound one for graphics. But the sound is only playback of an existing file (no processing) through [sfplay] so my intuition is that it doesn't make much sense in terms of computation load. 4) I don't work with Jack bacause I get x_run errors and added noise.
any other ideas?
thanks Oded