You may want to try to get the outlook 2007 sp1 Client to run with CRM 4.0. We upgraded from Outlook2003. My laptop has 2 gigs and crm usage at a high is at 1200mb processing and runs fine. Desktop users are running at 700 mb processing with 512mb and 1G of memory. One oddity is that most systems are fine but some hard drives just dont adjust and when we swap hardrives, the users outlook runs fine.