Should England overcome Italy at Twickenham on March 10, then they would travel to the Millennium Stadium knowing that victory against Wales would hand them their first Grand Slam since 2003.
"England have been very clinical. They know how to win games - when to put it up the jumper, when to play. They are the team to beat this year," North told PA.
"They are leading the table with two games to go. You never know what is going to happen against Italy, who showed against France they can perform. But when England come to Cardiff, it will be all or nothing, I guess."
North has made 29 appearances for his country.