Update:

>> there's an interesting tweet by IBM from June 2011 which seems to confirm that
>> the Wii U actually uses the very same POWER7 *chip* (not just the same core) as
>> IBM's Watson computer, which would mean an eight-core POWER7 chip. I find that
>> very hard to believe.

> If the recent information about Wii U's CPU being a three-core chip is true, this
> would mean that IBM purposely spread false information in June 2011. There's not
> even a POWER7 chip with 3 cores (4 cores being the smallest variant). And from
> last month two other tweets from the same IBM twitter account that, citing an
> old Engadget article, suddenly read way more vague and contradict the older tweet
> (same chip as in Watson vs. custom chip):
> http://twitter.com/IBMWatson/status/231902074890248192
> http://twitter.com/IBMWatson/status/240241146213842944

2 months ago, IBM reinforced the claim that the Wii U processor was based on POWER7:

http://twitter.com/IBMWatson/status/247460688283463680

Only few days later, IBM finally admitted that their claim that the Wii U processor was a POWER7 chip of some sort or somehow derived from POWER7 was a misinformation:

http://twitter.com/IBMWatson/status/248820933618442240
http://twitter.com/IBMWatson/status/248929547842641920