The reason why your clients received huge performance boost is not only because of Internet connectionBut also there is a lot of internal communication between the different zones of firewall as well like constant chat with active directory , constan...

Which version of ASA u r running on?If u r using 8.4 then u Will use private addresses while applying acl for interesting traffic on wan interfaceIf u r using 8.0 version then u will use public addresses while applying acl for interesting traffic on ...