The storage statement above about precision is incorrect.("6 bytes for precisions less than 3; 7 bytes for precisions 4 and 5. All other precisions require 8 bytes. ")
Try this example from the SQL Katmai blog:
http://www.sqlkatmai.com/2008/06/sql-server-2008-katmai-tsql_26.html
DECLARE
@dt1 AS DATETIME2 = SYSDATETIME(),
@dt2 AS DATETIME2(0) = SYSDATETIME(),
@dt3 AS DATETIME2(1) = SYSDATETIME(),
@dt4 AS DATETIME2(2) = SYSDATETIME(),
@dt5 AS DATETIME2(3) = SYSDATETIME(),
@dt6 AS DATETIME2(4) = SYSDATETIME(),
@dt7 AS DATETIME2(5) = SYSDATETIME(),
@dt8 AS DATETIME2(6) = SYSDATETIME(),
@dt9 AS DATETIME2(7) = SYSDATETIME()
SELECT
DATALENGTH(@dt1),--8 BYTES
DATALENGTH(@dt2),--6 BYTES
DATALENGTH(@dt3),--6 BYTES
DATALENGTH(@dt4),--6 BYTES
DATALENGTH(@dt5),--7 BYTES
DATALENGTH(@dt6),--7 BYTES
DATALENGTH(@dt7),--8 BYTES
DATALENGTH(@dt8),--8 BYTES
DATALENGTH(@dt9) --8 BYTES
Assuming the blog is correct, storage is this:
precisions 0,1,2 - 6 bytes
precisions 3,4 - 7 bytes
precisions 5,6,7 - 8 bytes