If you need to test the new RemoteFX or Dynamic Memory features in W2K8R2 RDS or Hyper-V respectively, then you can download the beta of the upcoming first service pack for Windows Server 2008 R2 (and Windows 7 for the client-side bits) here . I wouldn’t bother installing the beta service pack on a Windows...

Windows Service Packs are traditionally roll-up packages of hotfixes into a single, manageable package for easier updating of the OS to a known (minimum) state – they almost certainly contain extra changes that were not in any package delivered through Windows Update (LDRs) and occasionally other changes...