We operate a Windows 2003 Active Directory network. As the new IT manager I've inherited this infrastructure from previous outside contractors that have come in to help maintain our company network. The network is composed of approximately 30% Windows 7 Domain Members, 20% Windows (XP/7/Vista) Workgroup members and the rest Mac OS X (not bound to AD Domain).
We're going to be updating our server infrastructure to Windows Server 2008 R2 and I'm therefore considering consolidating the network infrastructure.
My question is should I add/bind the 70% of computers not in the domain to Active Directory? What is, if any, the network performance impact of having a mixed environment like this? Bearing in mind that a lot of network file sharing goes on between client computers and also our central file server, I wouldn't want there to be excess authentication chatter as a result? I know also there are benefits to having domain members such as Group Policies and centralised authentication.
Any help or pointers much appreciated!