When I was responsible for building and running in Exchange 2000 Clusters; if I put 2GB or 3GB of RAM in a box and Store *didn't* use 1.2GB on average (well, obviously user load is a factor here) then I KNEW I had a problem with that box. 1.2GB of RAM and idling on 3 to 4% CPU is a happy cluster node that'll run for months in that state - reboot - are you mad?
When you're supporting gobs of users on the one Exchange server, shouldn't it be a dedicated server, and shouldn't it use as much physical RAM as possible? In memory ops are so much more performant than those that must refer out to the page...
Next stop - fast fast FAST transaction log volumes :-) - then 2000 / 3000 corp users *concurrent* per box should be no problem at all.
Cheers
Microsoft
