But Wales' ever-green flanker reckons the Irish province's triumph will not give former Munster coach Declan Kidney and his men a psychological edge on their return to the Welsh capital.
Williams said: "I don't think Munster's record will play a part. We've had happy memories of playing in Cardiff and we'll try to use that to our advantage.
"I'm sure they will have enjoyed themselves but this is a totally different environment.
"I can guarantee that when they played their two final's in Cardiff, they would have had at least 80 per cent Munster supporters - it won't be like that on Saturday.
"Ireland deserve to be in the position they're in because they have been the best side in the tournament. But a lot can change after one game and with home advantage, we've got to use that."
Wales must win by 13 points to clinch back-to-back Six Nations championships for the first time in 30 years. And Williams, capped 87 times, reckons that success would eclipse the 2008 Grand Slam triumph.
Williams said: "For us, it would be a better achievement than winning last season's Grand Slam. No-one expected that but everyone has put the pressure on this year.
"It's a measure of how far we've come. And if we can make up the 13 points difference, it will be a bigger achievement.
In order to do so, Cardiff Blues' veteran Williams has singled out the centre partnership of 2005 British Lions captain Brian O'Driscoll and Gordon D'Arcy as Ireland's dangerman.
Williams said: "Brian has been awesome and the stand-out player of the Six Nations again. Everyone had written him off but he's a world-class player. He's great with or without the ball and is a major player.
"Brian and Gordon has been there before and know what to do. They are like having two extra number seven's on the park. They are all over everything.
"I watched Gordon for Leinster against the Ospreys recently and he was brilliant. Their backs are more dangerous than ever before."
Wales: Lee Byrne; Mark Jones, Tom Shanklin, Gavin Henson, Shane Williams; Stephen Jones, Mike Phillips; Gethin Jenkins, Matthew Rees, Adam Jones, Ian Gough, Alun-Wyn Jones, Ryan Jones (capt), Martyn Williams, Andy Powell.
Replacements: Huw Bennett, John Yapp, Luke Charteris, Dafydd Jones, Warren Fury, James Hook, Jamie Roberts.
Ireland: Rob Kearney; Tommy Bowe, Brian O'Driscoll (capt), Gordon D'Arcy, Luke Fitzgerald; Ronan O'Gara, Tomas O'Leary; Marcus Horan, Jerry Flannery, John Hayes, Donncha O'Callaghan, Paul O'Connell (capt), Stephen) Ferris, David Wallace, Jamie Heaslip.
Replacements: Rory Best, Tom Court, M O'Driscoll, Denis Leamy, Peter Stringer, Paddy Wallace, Geordan Murphy.