Backup 4.0 and Backup 4.0.1 have the same functionality
Requirements for Each Managed Machine
256 MB of RAM
750 MB of free disk space
Microsoft Windows 2000, XP, 2003, 2003 R2, Vista, 2008, 2008 R2, 7.
Backup 3.2 and later supports Windows Server 2008, Windows Server 2008 R2 and Windows 7. Backup and Disaster Recovery 3.1 supports Windows Server 2008, but does not support Windows Server 2008 R2 and Windows 7.