http://blogs.technet.com/b/puneetvig/archive/2010/08/14/storage-improvements-from-windows-server-2008-sp1-hyper-v-to-windows-server-2008-r2-hyper-v.aspx  The following table shows changes in storage.  Some of the changes are performance related like hot add of storage.  This helps performance by reducing the time it takes to add new storage.  The big things to note are increases inen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)