According to DRCs investigation, vncviewer on OS X is much slower than on other platforms: http://sourceforge.net/mailarchive/forum.php?thread_name=51314991.7070105%40users.sourceforge.net&forum_name=virtualgl-users "The FLTK performance on OS X still seems like a bug. Hard to believe that it would really be 10x slower than Java."
Closing as a duplicate of a newer bug since the other bug contains more information. *** This bug has been marked as a duplicate of bug 5415 ***