Hi, not really a dovecot issue but, im running dovecot 1.0.10 with no issues for awhile now J.
However I ran into an issue today where postfix didn't have enough processes to handle incoming smtp connections. This for whatever reason was causing pop/imap (dovecot) to take a long time to respond on the appropriate port.
After looking at server and finding nothing wrong I stopped postfix which got rid of the delay on port 110/143. I then turned on postfix again and saw the delay for port 25/110/143. What I then did was adjust/increase the default_process_limit in postfix which took care of the problem.
Question is why would not enough processes in postfix slow other services down like dovecot 110/143? There was plenty of bandwith/mem/cpu left.