How much higher? Can you check the individual dovecot processes' CPU usage? I guess mainly director, imap-login and pop3-login. The director code should be pretty much the same though.one server of the ring is now running Dovecot 2.3.7 and works fine with the others Dovecot 2.2 since 3 days.I notice only that the load avarage of this CentOS 7 server is higher compared with CentOS 6 and Dovecot 2.2, but I don't know if is related to the new operating system or Dovecot (hardware is the same).