Refer this https://msdn.microsoft.com/en-us/library/ms182776.aspx

both has same format "YYYY-MM-DD HH:MM:SS" . on storage date time takes 8 bytes and time stamp takes 4 bytes. Then major difference is the date time is what westore is what we get but in time stamp effected by the server timezone setting.

The supported range for DATETIME type is ‘1000-01-01 00:00:00' to ‘9999-12-31 23:59:59', where as the supported range for TIMESTAMP type is ‘1970-01-01 00:00:01' UTC to ‘2038-01-19 03:14:07' UTC.