One pointer!!!
Make sure you select the right Noctua
Socket 2011 only - http://www.overclockers.co.uk/showproduct.php?prodid=HS-015-NC&groupid=701&catid=57&subcat=1395
The one you want that fits the rest - http://www.overclockers.co.uk/showproduct.php?prodid=HS-011-NC&groupid=701&catid=57&subcat=1395