installing two addtional hdd's in RAID1, the previous is going into server acting as file server and also domain controller, primarily as a domain controller and mail server. Currently data is all on existing HDD with O/S etc. Would you expect data/file serving to increase in speed with the data being shifted to additional drives and leaving other two drives to look after domain control stuff? reason for change is to separate data from os and also to hopefully gain some increase in speed for data serving for files etc