Due to the Windows 2008 R2 limitation in supporting Westmere-EX CPUs, it can be installed for X8OBN systems with a reduced configuration of 4 Westmere-EX CPUs, but not the full configuration of 8 Westmere-EX CPUs.
Windows 2008 R2 with SP1 is needed for supporting the full X8OBN configuration of 8 Westmere-EX CPUs.