Dovecot and imapproxy

imapproxy sped things up a lot for me when I was using courier. I switched to dovecot a while back and kept using imapproxy. Lately I've been noticing weird TCP Queuing spikes in my munin graphs and discontinuing my use of imapproxy seems to have smoothed them out completely and I haven't noticed a slowdown in webmail. Is imapproxy generally not necessary with dovecot?

• Grant