Sorry John, Exchange & OWA installed on seperate machine of xeon 1,8ghz dual processor 1GB Ram. Just using this box (ex PC) to trial ISA. Primary use as firewall, vpn access point, and caching. When I roll ISA out it will be on a higher spec machine, using a 10-15K SCSI disk, xeon, and at least 512 ram - depending on what offers are on from the like of Dell.