A little confused... for posters who fly out of Rochester and you asked how crowded is SYR? I am guessing you meant to ask about ROC the Rochester Airport? Rochester is crowded on weekday mornings with business travelers and less flights than there used to be so they are full. Rochester security checkpoint is annoyingly slow compared to others. The good news is they finally got a real luggage scanner so no more extra line to have your luggage scanned. If you are checking luggage get to the check-in no later than 5AM. I would target 4:45, through check-in and security by 5:15, get a coffee, boarding could start 5:45 if it's a full size jet. You could slide a little later if it's a region jet, those board 15-20 minutes prior to departure.