http://www.activewin.com/awin/commen...ineIndex=43495

Microsoft would like us to believe that Windows Vista and Server 2008 are
basically the same and use the same codebase but the two differ slightly in
certain areas. It appears that Server 2008 performs better in almost every
sense of the term but benchmarks have failed to pin down the exact reason
why.
We previously reported that Server 2008 performed almost 20% faster in some
cases than what is supposed be its closely related cousin, Vista.

The Register reports that part of the reason that Server 2008 doesn't get
the same negative press that Vista does is because it delivers features that
people actually want.