In this video, Bill the Server Guy
explains the new features and performance improvements of the Xeon E5-2600 series platform.
Today just about every vendor you could name announced new servers based on the new platform. If you don't have the time to wade through all the press releases and the content-free slide deck
that Intel put out, I think this video provides what you need to know in a nicely wrapped package.
For a thorough writeup on Sandy Bridge E5, I recommend this writeup by Timothy Prickett Morgan
at The Register.