http://blogs.technet.com/momteam/archive/2007/08/10/acs-sizing-guidance-in-progress.aspxI am in the process of updating the Operations Manager 2007 Performance and Scalability white paper to include ACS sizing guidance. When completed in a couple weeks, it will be posted to the Download Center ( http://www.microsoft.com/downloads/details.aspx?FamilyID=d043a72a-9a96-446d-b70a-1807fb263ce4&DisplayLang=enen-USCommunityServer 2.1 SP1 (Build: 61025.2)