Recently-retired veteran Stewart is more than qualified to speak on the subject, having made the same switch on the country's first-ever August transfer deadline day in 2002.
"Ipswich fans are passionate but it is a whole new level up there," Stewart told the Sunday Sun. "The Sunderland fans are among some of the most impatient in the world.
"And, having spent all that money on him, there will be pressure on him to come up with the goods right from the start. They certainly let you know if they're not happy."