This rumor comes from IGN and a rumor going around.

…the Xbox 720’s raw graphics processing power is expected to be six times that of the Xbox 360 and will yield 20-percent greater performance than Nintendo’s forthcoming console, the Wii U.

 

You are smart so I am sure you already figured this out. If this rumor is true the Wii U is 5 times more powerful than the current generation.

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