jQuery slide function is jittery, not smooth, popping

jQuery slide function is jittery, not smooth, popping

I have read about a zillion forum posts on this issue and still no joy.
 
I am using some pretty simple code:
  1.     $(function () {
  2.          $('div.content div').slideUp(0);
  3.          $('div.content p').click(function () {
  4.             $(this).next().slideToggle(500);
  5.          });
  6.     });
              Here is an example where you can see it.
              http://islandnet.com/~ric0/seattlesalsacongress.com/faq1.html
                I have tried zeroing out padding margin etc but no luck.