I'm referring to this Technet article: http://technet.microsoft.com/en-us/library/dd346700.aspx It looks like the minimum supported memory and the maximum recommended (taking # of cores into account) are the same - in some cases (Edge and Hub). So does this mean that, if we go by the book, we should be running Edge and Hub roles on servers with no less than 4 cores, so either two dual core processors or a single quad core??? Currently, I'm running a Exchange 2007 server (MB, CAS, HT) with 8 GB of RAM and 1 dual-core processor. So with Exchange 2010, you need at least 4 cores for a single role? The assumption must be that if you've separated the roles on different servers you have a pretty decent workload? As opposed to someone who can get away with all roles on a single server?

So does this mean that, if we go by the book, we should be running Edge and Hub roles on servers with no less than 4 cores, so either two dual core processors or a single quad core??? Not sure what "by the book" you are referencing. The link: http://technet.microsoft.com/en-us/library/dd346699.aspx States that the absolute minimum for a Hub or ET is 1xcore and max is 12xcore. Going back to your original post, the minimum RAM for a Hub or ET is 4 GB, no matter how many cores you have. It really depends on your environment and workload. If you use the Mailbox Calculator, based on your user profile entered, it will tell you how many cores you need for your specific environment, then you can determine RAM requirements. http://msexchangeteam.com/archive/2009/11/09/453117.aspxTim Harrington | MVP: Exchange | MCITP: EMA 2007/2010, MCITP: Server 2008, MCTS: OCS | Blog: http://HowDoUC.blogspot.com | Twitter: @twharrington