From neogaf explaining the posible rumor "720 will be x6 360 and 20% more powerfull than wii u"
http://en.wikipedia.org/wiki/Compari...on_R400_series
http://en.wikipedia.org/wiki/FLOPS
We'll be using this AMD GPU wiki for reference to the #'s i'm about to dish out. Also linked is a wiki on what a FLOP is and what it means if you need it.
(1 GFLOPS = 1 billion FLoating-point OPerations per Second, 1000 GFLOPS = 1 TFLOP)
Xbox 360 GPU = 240 GFLOPS
AMD HD 6670 (rumored to be in a dual setup f/ the Xbox 720) = 768 GFLOPS X 2 = 1536 GFLOPS
AMD HD 4870 (the rumored RV770 in Wii U) = 1200 GFLOPS
1536/240 = 6.4 which is where they get the whole "6x more powerful than 360 thing"
1200/240 = 5 which is where they get the whole "5x more powerful than 360 thing"
(1536-1200)/1536= 0.21875 which is where they get the whole "Xbox 720 is 20% stronger than Wii U thing"
IT'S ALL BS PEOPLE. It's all nonsense speculation that anyone can do as I proved above.
Oh, and the Wii U will not be limited to a single thread. It's rumored to be a tri-core IBM cpu based on "Watson" aka the Power7 CPU from IBM which does out of order execution, and does 4..YES FOUR simultaneous threads per core...so that tri-core would do 12 threads.