Poor Roundcube performance with default configuration

[Brady, Mike]

Mileage may well vary on this one but I thought that others may be 
interested in this observation.

With a default configuration of Kolab 3.1 on a single Centos 6.5 box I 
have found Roundcube performance to be not great.

By default configuration I mean nothing more than

yum install kolab
setup-kolab

has been done.

I have found that disabling imap_cache and messages_cache significantly 
improves Roundcube performance.  These settings can be found in 
/etc/roundcube/config.inc.php.  I notice that what I assume to be the 
Roundcube defaults in /etc/roundcube/defaults.inc.php is for these to be 
disabled.

Tuning mysql (which I haven't done) may well improve things, but I have 
to wonder if it is worth the additional overhead of running a mysql 
cache for Roundcube with a default all in one installation of the Kolab 
components?

Thoughts?

Regards

Mike